@article {pmid30655189,
year = {2019},
author = {Barstow, BA and Vice, J and Bowman, S and Mehta, T and Kringen, S and Axelson, P and Padalabalanarayanan, S},
title = {Examining perceptions of existing and newly created accessibility symbols.},
journal = {Disability and health journal},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dhjo.2018.11.012},
pmid = {30655189},
issn = {1876-7583},
abstract = {BACKGROUND: Symbols are used to convey messages in a clear, understandable manner, without the use of written language. The most widely recognized symbol used to denote access for persons with disabilities is the International Symbol of Access. This symbol has been criticized for its inadequate representation of disability diversity poorly representing universal design of space and products.

OBJECTIVE: This descriptive study explored individual comprehension and perceptions of nine existing and newly created accessibility pictograph symbols and identified one that represented universal access to fitness equipment.

METHODS: A survey was disseminated electronically and face-to-face to individuals, groups and organizations affiliated with inclusive fitness equipment, space and programming. Quantitative data was analyzed for descriptive statistics, rank order of symbols and group comparisons of rankings. Thematic analysis of open-ended question results revealed themes to enhance understanding of symbol rank order.

RESULTS: 981 participants completed the survey. Symbol four, shaped as a Venn diagram containing three icons representing individuals with varying ability levels, was ranked highest with no significant differences in group comparisons between participants with and without a disability and U.S. residents versus non-U.S. residents. 85.4% of participants demonstrated accurate comprehension of this symbol. Though symbol five had the same symbol rank median value, this symbol's distribution of scores was lower.

CONCLUSIONS: Participants accurately comprehended symbol four and it was identified as the highest ranked symbol representing universal access to fitness equipment. Because of symbol unfamiliarity, adoption will require education and consistency of use and placement.},
}
@article {pmid30639341,
year = {2019},
author = {Lohr, JN and Galimov, ER and Gems, D},
title = {Does senescence promote fitness in Caenorhabditis elegans by causing death?.},
journal = {Ageing research reviews},
volume = {50},
number = {},
pages = {58-71},
doi = {10.1016/j.arr.2019.01.008},
pmid = {30639341},
issn = {1872-9649},
abstract = {A widely appreciated conclusion from evolutionary theory is that senescence (aging) is of no adaptive value to the individual that it afflicts. Yet studies of Caenorhabditis elegans and Saccharomyces cerevisiae are increasingly revealing the presence of processes which actively cause senescence and death, leading some biogerontologists to wonder about the established theory. Here we argue that programmed death that increases fitness could occur in C. elegans and S. cerevisiae, and that this is consistent with the classic evolutionary theory of aging. This is because of the special conditions under which these organisms have evolved, particularly the existence of clonal populations with limited dispersal and, in the case of C. elegans, the brevity of the reproductive period caused by protandrous hermaphroditism. Under these conditions, death-promoting mechanisms could promote worm fitness by enhancing inclusive fitness, or worm colony fitness through group selection. Such altruistic, adaptive death is not expected to evolve in organisms with outbred, dispersed populations (e.g. most vertebrate species). The plausibility of adaptive death in C. elegans is supported by computer modelling studies, and new knowledge about the ecology of this species. To support these arguments we also review the biology of adaptive death, and distinguish three forms: consumer sacrifice, biomass sacrifice and defensive sacrifice.},
}
@article {pmid30629594,
year = {2019},
author = {Narasimha, S and Nagornov, KO and Menin, L and Mucciolo, A and Rohwedder, A and Humbel, BM and Stevens, M and Thum, AS and Tsybin, YO and Vijendravarma, RK},
title = {Drosophila melanogaster cloak their eggs with pheromones, which prevents cannibalism.},
journal = {PLoS biology},
volume = {17},
number = {1},
pages = {e2006012},
doi = {10.1371/journal.pbio.2006012},
pmid = {30629594},
issn = {1545-7885},
abstract = {Oviparous animals across many taxa have evolved diverse strategies that deter egg predation, providing valuable tests of how natural selection mitigates direct fitness loss. Communal egg laying in nonsocial species minimizes egg predation. However, in cannibalistic species, this very behavior facilitates egg predation by conspecifics (cannibalism). Similarly, toxins and aposematic signaling that deter egg predators are often inefficient against resistant conspecifics. Egg cannibalism can be adaptive, wherein cannibals may benefit through reduced competition and added nutrition, but since it reduces Darwinian fitness, the evolution of anticannibalistic strategies is rife. However, such strategies are likely to be nontoxic because deploying toxins against related individuals would reduce inclusive fitness. Here, we report how D. melanogaster use specific hydrocarbons to chemically mask their eggs from cannibal larvae. Using an integrative approach combining behavioral, sensory, and mass spectrometry methods, we demonstrate that maternally provisioned pheromone 7,11-heptacosadiene (7,11-HD) in the eggshell's wax layer deters egg cannibalism. Furthermore, we show that 7,11-HD is nontoxic, can mask underlying substrates (for example, yeast) when coated upon them, and its detection requires pickpocket 23 (ppk23) gene function. Finally, using light and electron microscopy, we demonstrate how maternal pheromones leak-proof the egg, consequently concealing it from conspecific larvae. Our data suggest that semiochemicals possibly subserve in deceptive functions across taxa, especially when predators rely on chemical cues to forage, and stimulate further research on deceptive strategies mediated through nonvisual sensory modules. This study thus highlights how integrative approaches can illuminate our understanding on the adaptive significance of deceptive defenses and the mechanisms through which they operate.},
}
@article {pmid30624681,
year = {2019},
author = {Aumer, D and Stolle, E and Allsopp, M and Mumoki, F and Pirk, CWW and Moritz, RFA},
title = {A single SNP turns a social honey bee (Apis mellifera) worker into a selfish parasite.},
journal = {Molecular biology and evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/molbev/msy232},
pmid = {30624681},
issn = {1537-1719},
abstract = {The evolution of altruism in complex insect societies is arguably one of the major transitions in evolution and inclusive fitness theory plausibly explains why this is an evolutionary stable strategy. Yet, workers of the South African Cape honey bee (Apis mellifera capensis) can reverse to selfish behaviour by becoming social parasites and parthenogenetically producing female offspring (thelytoky). Using a joint mapping and population genomics approach, in combination with a time-course transcript abundance dynamics analysis, we show that a single nucleotide polymorphism (SNP) at the mapped thelytoky locus (Th) is associated with the iconic thelytokous phenotype. Th forms a linkage group with the ecdysis triggering hormone receptor (Ethr) within a non-recombining region under strong selection in the genome. A balanced detrimental allele system plausibly explains why the trait is specific to A. m. capensis and cannot easily establish itself into genomes of other honey bee subspecies.},
}
@article {pmid30564400,
year = {2018},
author = {Hare, D and Blossey, B and Reeve, HK},
title = {Value of species and the evolution of conservation ethics.},
journal = {Royal Society open science},
volume = {5},
number = {11},
pages = {181038},
doi = {10.1098/rsos.181038},
pmid = {30564400},
issn = {2054-5703},
abstract = {The theory of evolution by natural selection can help explain why people care about other species. Building upon recent insights that morality evolves to secure fitness advantages of cooperation, we propose that conservation ethics (moral beliefs, attitudes, intuitions and norms regarding other species) could be adaptations that support cooperation between humans and non-humans. We present eco-evolutionary cost-benefit models of conservation behaviours as interspecific cooperation (altruism towards members of other species). We find that an evolutionary rule identical in structure to Hamilton's rule (which explains altruistic behaviour towards related conspecifics) can explain altruistic behaviour towards members of other species. Natural selection will favour traits for selectively altering the success of members of other species (e.g. conserving them) in ways that maximize inclusive fitness return benefits. Conservation behaviours and the ethics that evolve to reinforce them will be sensitive to local ecological and socio-cultural conditions, so will assume different contours in different places. Difficulties accurately assessing costs and benefits provided by other species, time required to adapt to ecological and socio-cultural change and barriers to collective action could explain the apparent contradiction between the widespread existence of conservation ethics and patterns of biodiversity decline globally.},
}
@article {pmid30557568,
year = {2018},
author = {Eshel, I},
title = {Mutual altruism and long-term optimization of the inclusive fitness in multilocus genetic systems.},
journal = {Theoretical population biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.tpb.2018.10.005},
pmid = {30557568},
issn = {1096-0325},
abstract = {The dynamics of long-term evolution in a complex genetically-structured population with a flux of random mutations is employed here to study the evolution of mutual altruism between relatives that are encountered repeatedly, where the level of altruism is measured by the risk one is willing to accept in order to save the life of one's relative. It is shown that regardless of the number of loci involved, of the rates of recombination among them, and of the intensity of the selection forces, the long-term dynamics can phenotypically converge only to a level of altruism that maximizes the individual inclusive fitness as it ha previously defined by students of the individual approach to evolution. Except for the widely studied case of weak selection, however, the convergence to such a level of altruism is not necessarily generation-to-next monotone. It is further shown that, unlike the case of the one-shot encounter, repeated encounters between relatives allows for more than one level of altruism which may maximize the inclusive fitness, in which case not all such levels of altruism are evolutionarily accessible.},
}
@article {pmid30545205,
year = {2000},
author = {Gould, L},
title = {Adoption of a Wild orphaned ringtailed lemur infant by natal group members: Adaptive explanations.},
journal = {Primates; journal of primatology},
volume = {41},
number = {4},
pages = {413-419},
doi = {10.1007/BF02557652},
pmid = {30545205},
issn = {1610-7365},
abstract = {In December 1992 an infant ringtailed lemur, approximately 7 weeks of age, was orphaned in one of the regularly-censused social groups at the Beza-Mahafaly Reserve, southwestern Madagascar. The infant was initially adopted by a subadult (2 yr-old) male from the group. Continuous-time focal animal data were collected for a 12-hr period, from the time that the infant was retrieved by the young male, in order to document the adoption process. Ten members of the infant's social group (total group number=18) engaged in infant care behaviors over the 12-hr period. The subadult male spent the most time engaged in infant care, and he and one adult female exhibited the highest frequency of caregiving behaviors over the 12-hr period (p<0.001). Four adult males also initially cared for the infant. The orphan was one of only six infants in the reserve population to survive that year. She was censused two years later as an adolescent member of her natal group. Adaptive explanations for this adoption vary depending upon the care-giver. For the subadult male and adult female caregivers, kin selection can be suggested, as the infant was related to all females and immature animals in the group. Adult males may have exhibited caregiving behaviors as a strategy related to affiliation with adult females which could lead to potential mating and reproductive success.},
}
@article {pmid30464831,
year = {2018},
author = {Clarke, PMR and McElreath, MB and Barrett, BJ and Mabry, KE and McElreath, R},
title = {The evolution of bequeathal in stable habitats.},
journal = {Ecology and evolution},
volume = {8},
number = {21},
pages = {10594-10607},
doi = {10.1002/ece3.4549},
pmid = {30464831},
issn = {2045-7758},
abstract = {Adults sometimes disperse, while philopatric offspring inherit the natal site, a pattern known as bequeathal. Despite a decades-old empirical literature, little theoretical work has explored when natural selection may favor bequeathal. We present a simple mathematical model of the evolution of bequeathal in a stable environment, under both global and local dispersal. We find that natural selection favors bequeathal when adults are competitively advantaged over juveniles, baseline mortality is high, the environment is unsaturated, and when juveniles experience high dispersal mortality. However, frequently bequeathal may not evolve, because the fitness cost for the adult is too large relative to inclusive fitness benefits. Additionally, there are many situations for which bequeathal is an ESS, yet cannot invade the population. As bequeathal in real populations appears to be facultative, yet-to-be-modeled factors like timing of birth in the breeding season may strongly influence the patterns seen in natural populations.},
}
@article {pmid30457220,
year = {2018},
author = {Amici, F},
title = {An Evolutionary Approach to the Study of Collaborative Remembering?.},
journal = {Topics in cognitive science},
volume = {},
number = {},
pages = {},
doi = {10.1111/tops.12398},
pmid = {30457220},
issn = {1756-8765},
abstract = {Hope and Gabbert (2008) and Jay and colleagues (in press) show us that collaborative remembering, in certain contexts, may result in incomplete and less accurate memories. Here, I will discuss the evolutionary origins of this behavior, linking it to phenomena such as social contagion, conformity, and social learning, which are highly adaptive and widespread across non-human taxa.},
}
@article {pmid30455506,
year = {2018},
author = {Ruiz-Lambides, AV and Weiß, BM and Kulik, L and Widdig, A},
title = {Which male and female characteristics influence the probability of extragroup paternities in rhesus macaques, Macaca mulatta?.},
journal = {Animal behaviour},
volume = {140},
number = {},
pages = {119-127},
doi = {10.1016/j.anbehav.2018.04.018},
pmid = {30455506},
issn = {0003-3472},
support = {P40 OD012217/OD/NIH HHS/United States ; },
abstract = {Extragroup paternity (EGP) is found across a wide range of species and may entail reproductive benefits, but may also entail costs to both sexes. While population and group parameters affecting the degree of EGPs are relatively well established, less is known about the individual characteristics that make males and females engage in alternative reproductive tactics such as EGP. Applying a combination of long-term demographic and genetic data from the rhesus macaque population of Cayo Santiago (Puerto Rico, U.S.A.), we investigate which male and female characteristics influence the probability of EGP to better understand the circumstances that shape the distribution and occurrence of EGP. Our results show that, against our expectations, higher-ranking females were more likely to produce EGP offspring than lower- ranking females. The probability of producing extragroup offspring was not significantly related to female or male age, male tenure or previous reproductive success. Furthermore, genetic relatedness between the parents did not affect the production of extragroup offspring, but extragroup offspring were more frequently produced early rather than late in a given mating season. Altogether, our analysis suggests that individual attributes and seasonal aspects create different opportunities and preferences for engaging in EGP as an alternative reproductive tactic. The observed patterns of EGP in rhesus macaques appear to be consistent with female mate choice for genetic benefits, which needs to be confirmed in future studies.},
}
@article {pmid30450066,
year = {2018},
author = {Antfolk, J and Lieberman, D and Harju, C and Albrecht, A and Mokros, A and Santtila, P},
title = {Opposition to Inbreeding Between Close Kin Reflects Inclusive Fitness Costs.},
journal = {Frontiers in psychology},
volume = {9},
number = {},
pages = {2101},
doi = {10.3389/fpsyg.2018.02101},
pmid = {30450066},
issn = {1664-1078},
abstract = {Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene's-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.},
}
@article {pmid30444662,
year = {2018},
author = {Mullon, C and Lehmann, L},
title = {Eco-Evolutionary Dynamics in Metacommunities: Ecological Inheritance, Helping within Species, and Harming between Species.},
journal = {The American naturalist},
volume = {192},
number = {6},
pages = {664-686},
doi = {10.1086/700094},
pmid = {30444662},
issn = {1537-5323},
abstract = {Understanding selection on intra- and interspecific interactions that take place in dispersal-limited communities is a challenge for ecology and evolutionary biology. The problem is that local demographic stochasticity generates eco-evolutionary dynamics that are generally too complicated to make tractable analytical investigations. Here we circumvent this problem by approximating the selection gradient on a quantitative trait that influences local community dynamics, assuming that such dynamics are deterministic with a stable fixed point. The model nonetheless captures unavoidable kin selection effects arising from demographic stochasticity. Our approximation reveals that selection depends on how an individual expressing a trait change influences (1) its own fitness and the fitness of its current relatives and (2) the fitness of its downstream relatives through modifications of local ecological conditions (i.e., through ecological inheritance). Mathematically, the effects of ecological inheritance on selection are captured by dispersal-limited versions of press perturbations of community ecology. We use our approximation to investigate the evolution of helping within species and harming between species when these behaviors influence demography. We find that altruistic helping evolves more readily when intraspecific competition is for material resources rather than for space, because in this case the costs of kin competition tend to be paid by downstream relatives. Similarly, altruistic harming between species evolves when it alleviates downstream relatives from interspecific competition. Beyond these examples, our approximation can help better understand the influence of ecological inheritance on a variety of eco-evolutionary dynamics in metacommunities, from consumer-resource and predator-prey coevolution to selection on mating systems with demographic feedbacks.},
}
@article {pmid30417945,
year = {2018},
author = {Thomson, CE and Hadfield, JD},
title = {No evidence for sibling or parent-offspring coadaptation in a wild population of blue tits, despite high power.},
journal = {Evolution; international journal of organic evolution},
volume = {},
number = {},
pages = {},
doi = {10.1111/evo.13642},
pmid = {30417945},
issn = {1558-5646},
support = {//EPSRC/ ; UF150696//Royal Society/ ; UF100660//Royal Society/ ; NE/F015275/1//Natural Environment Research Council/ ; NE/P000924/1//Natural Environment Research Council/ ; },
abstract = {Parent and offspring behaviors are expected to act as both the agents and targets of selection. This may generate parent-offspring coadaptation in which parent and offspring behaviors become genetically correlated in a way that increases inclusive fitness. Cross-fostering has been used to study parent-offspring coadaptation, with the prediction that offspring raised by non-relatives, or parents raising non-relatives, should suffer fitness costs. Using long-term data from more than 400 partially crossed broods of blue tits (Cyanistes caeruleus), we show that there is no difference in mass or survival between crossed and non-crossed chicks. However, previous studies for which the evidence for parent-offspring coadaptation is strongest compare chicks from fully crossed broods with those from non-crossed broods. When parent-offspring coadaptation acts at the level of the brood then partial cross-fostering experiments are not expected to show evidence of coadaptation. To test this, we performed an additional experiment (163 broods) in which clutches were either fully crossed, non-crossed, or partially crossed. In agreement with the long-term data, there was no evidence for parent-offspring coadaptation on offspring fitness despite high power. In addition there was no evidence of effects on parental fitness, nor evidence of sibling coadaptation, although the power of these tests was more modest.},
}
@article {pmid30401742,
year = {2018},
author = {Wang, C and Lu, X},
title = {Reply to Engelhardt et al.: Inclusive fitness does maintain a heritable altruism polymorphism in Tibetan ground tits.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {115},
number = {48},
pages = {E11210-E11211},
doi = {10.1073/pnas.1814991115},
pmid = {30401742},
issn = {1091-6490},
}
@article {pmid30397131,
year = {2018},
author = {Green, JP and Hatchwell, BJ},
title = {Inclusive fitness consequences of dispersal decisions in a cooperatively breeding bird, the long-tailed tit (Aegithalos caudatus).},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {115},
number = {47},
pages = {12011-12016},
doi = {10.1073/pnas.1815873115},
pmid = {30397131},
issn = {1091-6490},
abstract = {Natal dispersal is a demographic trait with profound evolutionary, ecological, and behavioral consequences. However, our understanding of the adaptive value of dispersal patterns is severely hampered by the difficulty of measuring the relative fitness consequences of alternative dispersal strategies in natural populations. This is especially true in social species, in which natal philopatry allows kin selection to operate, so direct and indirect components of inclusive fitness have to be considered when evaluating selection on dispersal. Here, we use lifetime reproductive success data from a long-term study of a cooperative breeder, the long-tailed tit Aegithalos caudatus, to quantify the direct and indirect components of inclusive fitness. We show that dispersal has a negative effect on the accrual of indirect fitness, and hence inclusive fitness, by males. In contrast, the inclusive, predominantly direct, fitness of females increases with dispersal distance. We conclude that the conflicting fitness consequences of dispersal in this species result in sexually antagonistic selection on this key demographic parameter.},
}
@article {pmid30381383,
year = {2018},
author = {Macfarlan, SJ and Erickson, PI and Yost, J and Regalado, J and Jaramillo, L and Beckerman, S},
title = {Bands of brothers and in-laws: Waorani warfare, marriage and alliance formation.},
journal = {Proceedings. Biological sciences},
volume = {285},
number = {1890},
pages = {},
doi = {10.1098/rspb.2018.1859},
pmid = {30381383},
issn = {1471-2954},
abstract = {The root of modern human warfare lies in the lethal coalitionary violence of males in small-scale societies. However, there is a paucity of quantitative data concerning the form and function of coalitionary violence in this setting. Debates exist over how lethal coalitions are constituted, as well as the motivations and benefits for males to join such groups. Data from a lowland Amazonian population, the Waorani of Ecuador, illuminate three issues: (i) the degree to which raiding parties are composed of groups of fraternal kin as opposed to strategic alliances of actual or potential affinal kin; (ii) the extent to which individuals use pre-existing affinal ties to motivate others to participate in war or leverage warfare as a mechanism to create such ties; and (iii) the extent to which participation in raiding is driven by rewards associated with future marriage opportunities. Analyses demonstrate that Waorani raiding parties were composed of a mix of males who were potential affines, actual affines and fraternal kin, suggesting that men used pre-existing genetic, lineal and social kin ties for recruiting raid partners and used raiding as a venue to create novel social relationships. Furthermore, analyses demonstrate that males leveraged raiding alliances to achieve marriage opportunities for themselves as well as for their children. Overall, it appears that a complex set of motivations involving individual rewards, kin marriage opportunities, subtle coercion and the assessment of alliance strength promote violent intergroup conflict among the Waorani. These findings illustrate the complex inter-relationships among kin selection, coalition building and mating success in our species.},
}
@article {pmid30381376,
year = {2018},
author = {Holen, ØH and Johnstone, RA},
title = {Reciprocal mimicry: kin selection can drive defended prey to resemble their Batesian mimics.},
journal = {Proceedings. Biological sciences},
volume = {285},
number = {1890},
pages = {},
doi = {10.1098/rspb.2018.1149},
pmid = {30381376},
issn = {1471-2954},
abstract = {Established mimicry theory predicts that Batesian mimics are selected to resemble their defended models, while models are selected to become dissimilar from their mimics. However, this theory has mainly considered individual selection acting on solitary organisms such as adult butterflies. Although Batesian mimicry of social insects is common, the few existing applications of kin selection theory to mimicry have emphasized relatedness among mimics rather than among models. Here, we present a signal detection model of Batesian mimicry in which the population of defended model prey is kin structured. Our analysis shows for most of parameter space that increased average dissimilarity from mimics has a twofold group-level cost for the model prey: it attracts more predators and these adopt more aggressive attack strategies. When mimetic resemblance and local relatedness are sufficiently high, such costs acting in the local neighbourhood may outweigh the individual benefits of dissimilarity, causing kin selection to drive the models to resemble their mimics. This requires model prey to be more common than mimics and/or well-defended, the conditions under which Batesian mimicry is thought most successful. Local relatedness makes defended prey easier targets for Batesian mimicry and is likely to stabilize the mimetic relationship over time.},
}
@article {pmid30380919,
year = {2018},
author = {Hernández Blasi, C and Mondéjar, L},
title = {Testing the Kundera Hypothesis: Does Every Woman (But Not Every Man) Prefer Her Child to Her Mate?.},
journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior},
volume = {16},
number = {4},
pages = {1474704918808864},
doi = {10.1177/1474704918808864},
pmid = {30380919},
issn = {1474-7049},
abstract = {The context of a famous novel by Milan Kundera (Immortality) suggests that when faced with a life-or-death situation, every woman would prefer to save her child than her husband, left hanging whether every man would do the same. We labeled this as the Kundera hypothesis, and the purpose of this study was to test it empirically as we believe it raises a thought-provoking question in evolutionary terms. Specifically, 197 college students (92 women) were presented a questionnaire where they had to make different decisions about four dilemmas about who to save (their mate or their offspring) in two hypothetical life-or-death situations: a home fire and a car crash. These dilemmas involved two different mate ages (a 25- or a 40-year-old mate) and two offspring ages (1- or a 6-year-old child). For comparative purposes, we also included complementary life-or-death dilemmas on both a sibling and an offspring, and a sibling and a cousin. The results generally supported the Kundera hypothesis: Although the majority of men and women made the decision to save their offspring instead of their mate, about 18% of men on average (unlike the 5% of women) consistently decided to save their mate across the four dilemmas in the two life-or-death situations. These data were interpreted with reference to Hamilton's inclusive fitness theory, the preferential role of women as kin keepers, and the evolution of altruism toward friends and mates.},
}
@article {pmid30372557,
year = {2018},
author = {Fortuna, TM and Namias, A and Snirc, A and Branca, A and Hood, ME and Raquin, C and Shykoff, JA and Giraud, T},
title = {Multiple infections, relatedness and virulence in the anther-smut fungus castrating Saponaria plants.},
journal = {Molecular ecology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mec.14911},
pmid = {30372557},
issn = {1365-294X},
support = {MULTIVIR ANR-13-BSV7-0008//Agence Nationale de la Recherche/ ; Fondation Louis D//French Academy of Science/ ; },
abstract = {Multiple infections (co-occurrence of multiple pathogen genotypes within an individual host) can have important impacts on diseases. Relatedness among pathogens can affect the likelihood of multiple infections and their consequences through kin selection. Previous studies on the castrating anther-smut fungus Microbotryum lychnidis-dioicae have shown that multiple infections occur in its host plant Silene latifolia. Relatedness was high among fungal genotypes within plants, which could result from competitive exclusion between unrelated fungal genotypes, from population structure or from interactions between plant and fungal genotypes for infection ability. Here, we aimed at disentangling these hypotheses using M. saponariae and its host Saponaria officinalis, both experimentally tractable for these questions. By analysing populations using microsatellite markers, we also found frequent occurrence of multiple infections and high relatedness among strains within host plants. Infections resulting from experimental inoculations in the greenhouse also revealed high relatedness among strains co-infecting host plants, even in clonally replicated plant genotypes, indicating that high relatedness within plants did not result merely from plant x fungus interactions or population structure. Furthermore, hyphal growth in vitro was affected by the presence of a competitor growing nearby and by its genetic similarity, although this latter effect was strain-dependent. Altogether, our results support the hypothesis that relatedness-dependent competitive exclusion occurs in Microbotryum fungi within plants. These microorganisms can thus respond to competitors and to their level of relatedness.},
}
@article {pmid30359363,
year = {2018},
author = {Dos Santos, M and Ghoul, M and West, SA},
title = {Pleiotropy, cooperation, and the social evolution of genetic architecture.},
journal = {PLoS biology},
volume = {16},
number = {10},
pages = {e2006671},
doi = {10.1371/journal.pbio.2006671},
pmid = {30359363},
issn = {1545-7885},
abstract = {Pleiotropy has been suggested as a novel mechanism for stabilising cooperation in bacteria and other microbes. The hypothesis is that linking cooperation with a trait that provides a personal (private) benefit can outweigh the cost of cooperation in situations when cooperation would not be favoured by mechanisms such as kin selection. We analysed the theoretical plausibility of this hypothesis, with analytical models and individual-based simulations. We found that (1) pleiotropy does not stabilise cooperation, unless the cooperative and private traits are linked via a genetic architecture that cannot evolve (mutational constraint); (2) if the genetic architecture is constrained in this way, then pleiotropy favours any type of trait and not especially cooperation; (3) if the genetic architecture can evolve, then pleiotropy does not favour cooperation; and (4) there are several alternative explanations for why traits may be linked, and causality can even be predicted in the opposite direction, with cooperation favouring pleiotropy. Our results suggest that pleiotropy could only explain cooperation under restrictive conditions and instead show how social evolution can shape the genetic architecture.},
}
@article {pmid30353655,
year = {2018},
author = {Li, XY and Kokko, H},
title = {Sex-biased dispersal: a review of the theory.},
journal = {Biological reviews of the Cambridge Philosophical Society},
volume = {},
number = {},
pages = {},
doi = {10.1111/brv.12475},
pmid = {30353655},
issn = {1469-185X},
support = {//Swiss National Science Foundation/ ; },
abstract = {Dispersal is ubiquitous throughout the tree of life: factors selecting for dispersal include kin competition, inbreeding avoidance and spatiotemporal variation in resources or habitat suitability. These factors differ in whether they promote male and female dispersal equally strongly, and often selection on dispersal of one sex depends on how much the other disperses. For example, for inbreeding avoidance it can be sufficient that one sex disperses away from the natal site. Attempts to understand sex-specific dispersal evolution have created a rich body of theoretical literature, which we review here. We highlight an interesting gap between empirical and theoretical literature. The former associates different patterns of sex-biased dispersal with mating systems, such as female-biased dispersal in monogamous birds and male-biased dispersal in polygynous mammals. The predominant explanation is traceable back to Greenwood's () ideas of how successful philopatric or dispersing individuals are at gaining mates or the resources required to attract them. Theory, however, has developed surprisingly independently of these ideas: models typically track how immigration and emigration change relatedness patterns and alter competition for limiting resources. The limiting resources are often considered sexually distinct, with breeding sites and fertilizable females limiting reproductive success for females and males, respectively. We show that the link between mating system and sex-biased dispersal is far from resolved: there are studies showing that mating systems matter, but the oft-stated association between polygyny and male-biased dispersal is not a straightforward theoretical expectation. Here, an important understudied factor is the extent to which movement is interpretable as an extension of mate-searching (e.g. are matings possible en route or do they only happen after settling in new habitat - or can females perhaps move with stored sperm). We also point out other new directions for bridging the gap between empirical and theoretical studies: there is a need to build Greenwood's influential yet verbal explanation into formal models, which also includes the possibility that an individual benefits from mobility as it leads to fitness gains in more than one final breeding location (a possibility not present in models with a very rigid deme structure). The order of life-cycle events is likewise important, as this impacts whether a departing individual leaves behind important resources for its female or male kin, or perhaps both, in the case of partially overlapping resource use.},
}
@article {pmid30338460,
year = {2018},
author = {Amici, F},
title = {Memories of emotional expressions in horses.},
journal = {Learning & behavior},
volume = {},
number = {},
pages = {},
doi = {10.3758/s13420-018-0363-9},
pmid = {30338460},
issn = {1543-4508},
abstract = {Proops, Grounds, Smith, and McComb (2018) suggest that horses remember previous emotional expressions of specific humans, and use these memories to adjust their behavior in future social interactions. Despite some methodological shortcomings, this study raises important questions on the complexity of social interactions in nonhuman animals, which surely deserve further attention.},
}
@article {pmid30320554,
year = {2018},
author = {van Veelen, M},
title = {Can Hamilton's rule be violated?.},
journal = {eLife},
volume = {7},
number = {},
pages = {},
doi = {10.7554/eLife.41901},
pmid = {30320554},
issn = {2050-084X},
abstract = {How generally Hamilton's rule holds is a much debated question. The answer to that question depends on how costs and benefits are defined. When using the regression method to define costs and benefits, there is no scope for violations of Hamilton's rule. We introduce a general model for assortative group compositions to show that, when using the counterfactual method for computing costs and benefits, there is room for violations. The model also shows that there are limitations to observing violations in equilibrium, as the discrepancies between Hamilton's rule and the direction of selection may imply that selection will take the population out of the region of disagreement, precluding observations of violations in equilibrium. Given what it takes to create a violation, empirical tests of Hamilton's rule, both in and out of equilibrium, require the use of statistical models that allow for identifying non-linearities in the fitness function.},
}
@article {pmid30310732,
year = {2018},
author = {Rodrigues, AMM},
title = {Resource availability and adjustment of social behaviour influence patterns of inequality and productivity across societies.},
journal = {PeerJ},
volume = {6},
number = {},
pages = {e5488},
doi = {10.7717/peerj.5488},
pmid = {30310732},
issn = {2167-8359},
abstract = {Animal societies vary widely in the diversity of social behaviour and the distribution of reproductive shares among their group members. It has been shown that individual condition can lead to divergent social roles and that social specialisation can cause an exacerbation or a mitigation of the inequality among group members within a society. This work, however, has not investigated cases in which resource availability varies between different societies, a factor that is thought to explain variation in the level of cooperation and the disparities in reproductive shares within each social group. In this study, I focus on how resource availability mediates the expression of social behaviour and how this, in turn, mediates inequality both within and between groups. I find that when differences in resource availability between societies persist over time, resource-rich societies become more egalitarian. Because lower inequality improves the productivity of a society, the inequality between resource-rich and resource-poor societies rises. When resource availability fluctuates over time, resource-rich societies tend to become more unequal. Because inequality hinders the productivity of a society, the inequality between resource-rich and resource-poor societies falls. From the evolutionary standpoint, my results show that spatial and temporal variation in resource availability may exert a strong influence on the level of inequality both within and between societies.},
}
@article {pmid30306126,
year = {2018},
author = {Ohkubo, Y and Yamamoto, T and Ogusu, N and Watanabe, S and Murakami, Y and Yagi, N and Hasegawa, E},
title = {The benefits of grouping as a main driver of social evolution in a halictine bee.},
journal = {Science advances},
volume = {4},
number = {10},
pages = {e1700741},
doi = {10.1126/sciadv.1700741},
pmid = {30306126},
issn = {2375-2548},
abstract = {Over the past decade, the cause of sociality has been much debated. Inclusive fitness [br in Hamilton's rule (br - c > 0)] has been criticized but is still useful in the organization of a framework by elucidating mechanisms through which br (benefit × relatedness) becomes larger than c (cost). The bee Lasioglossum baleicum is suitable for investigation of this issue because of the sympatric occurrence of both social and solitary nesting in its populations. We show that a large part (approximately 92%) of the inclusive fitness of a eusocial worker can be attributed to the benefits of grouping. A 1.5-fold relatedness asymmetry benefit in singly mated haplo-diploids explains a small part (approximately 8.5%) of the observed inclusive fitness. Sociality enables this species to conduct foraging and nest defense simultaneously, which is not the case in solitary nests. Our results indicate that this benefit of grouping is the main source of the increased inclusive fitness of eusocial workers.},
}
@article {pmid30305461,
year = {2018},
author = {Dyble, M and Gardner, A and Vinicius, L and Migliano, AB},
title = {Inclusive fitness for in-laws.},
journal = {Biology letters},
volume = {14},
number = {10},
pages = {},
doi = {10.1098/rsbl.2018.0515},
pmid = {30305461},
issn = {1744-957X},
abstract = {Cooperation among kin is common across the natural world and can be explained in terms of inclusive fitness theory, which holds that individuals can derive indirect fitness benefits from aiding genetically related individuals. However, human kinship includes not only genetic kin but also kin by marriage: our affines (in-laws) and spouses. Can cooperation between these genetically unrelated kin be reconciled with inclusive fitness theory? Here, we argue that although affinal kin and spouses do not necessarily share genetic ancestry, they may have shared genetic interests in future reproduction and, as such, can derive indirect fitness benefits though cooperating. We use standard inclusive fitness theory to derive a coefficient of shared reproductive interest (s) that predicts altruistic investment both in genetic kin and in spouses and affines. Specifically, a behaviour that reduces the fitness of the actor by c and increases the fitness of the recipient by b will be favoured by natural selection when sb > c We suggest that the coefficient of shared reproductive interest may provide a valuable tool for understanding not only the evolution of human kinship but also cooperation and conflict across the natural world more generally.},
}
@article {pmid30272235,
year = {2018},
author = {Minkner, MMI and Young, C and Amici, F and McFarland, R and Barrett, L and Grobler, JP and Henzi, SP and Widdig, A},
title = {Assessment of Male Reproductive Skew via Highly Polymorphic STR Markers in Wild Vervet Monkeys, Chlorocebus pygerythrus.},
journal = {The Journal of heredity},
volume = {109},
number = {7},
pages = {780-790},
doi = {10.1093/jhered/esy048},
pmid = {30272235},
issn = {1465-7333},
abstract = {Male reproductive strategies have been well studied in primate species where the ability of males to monopolize reproductive access is high. Less is known about species where males cannot monopolize mating access. Vervet monkeys (Chlorocebus pygerythrus) are interesting in this regard as female codominance reduces the potential for male monopolization. Under this condition, we assessed whether male dominance rank still influences male mating and reproductive success, by assigning paternities to infants in a population of wild vervets in the Eastern Cape, South Africa. To determine paternity, we established microsatellite markers from noninvasive fecal samples via cross-species amplification. In addition, we evaluated male mating and reproductive success for 3 groups over 4 mating seasons. We identified 21 highly polymorphic microsatellites (number of alleles = 7.5 ± 3.1 [mean ± SD], observed heterozygosity = 0.691 ± 0.138 [mean ± SD]) and assigned paternity to 94 of 97 sampled infants (96.9%) with high confidence. Matings pooled over 4 seasons were significantly skewed across 3 groups, although skew indices were low (B index = 0.023-0.030) and mating success did not correlate with male dominance. Paternities pooled over 4 seasons were not consistently significantly skewed (B index = 0.005-0.062), with high-ranking males siring more offspring than subordinates only in some seasons. We detected 6 cases of extra-group paternity (6.4%) and 4 cases of natal breeding (4.3%). Our results suggest that alternative reproductive strategies besides priority of access for dominant males are likely to affect paternity success, warranting further investigation into the determinants of paternity among species with limited male monopolization potential.},
}
@article {pmid30225081,
year = {2018},
author = {Konrad, CM and Gero, S and Frasier, T and Whitehead, H},
title = {Kinship influences sperm whale social organization within, but generally not among, social units.},
journal = {Royal Society open science},
volume = {5},
number = {8},
pages = {180914},
doi = {10.1098/rsos.180914},
pmid = {30225081},
issn = {2054-5703},
abstract = {Sperm whales have a multi-level social structure based upon long-term, cooperative social units. What role kinship plays in structuring this society is poorly understood. We combined extensive association data (518 days, during 2005-2016) and genetic data (18 microsatellites and 346 bp mitochondrial DNA (mtDNA) control region sequences) for 65 individuals from 12 social units from the Eastern Caribbean to examine patterns of kinship and social behaviour. Social units were clearly matrilineally based, evidenced by greater relatedness within social units (mean r = 0.14) than between them (mean r = 0.00) and uniform mtDNA haplotypes within social units. Additionally, most individuals (82.5%) had a first-degree relative in their social unit, while we found no first-degree relatives between social units. Generally and within social units, individuals associated more with their closer relatives (matrix correlations: 0.18-0.25). However, excepting a highly related pair of social units that merged over the study period, associations between social units were not correlated with kinship (p > 0.1). These results are the first to robustly demonstrate kinship's contribution to social unit composition and association preferences, though they also reveal variability in association preferences that is unexplained by kinship. Comparisons with other matrilineal species highlight the range of possible matrilineal societies and how they can vary between and even within species.},
}
@article {pmid30222228,
year = {2018},
author = {Townsend, AK and Taff, CC and Jones, ML and Getman, KH and Wheeler, SS and Hinton, MG and Logsdon, RM},
title = {Apparent inbreeding preference despite inbreeding depression in the American crow.},
journal = {Molecular ecology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mec.14866},
pmid = {30222228},
issn = {1365-294X},
abstract = {Although matings between relatives can have negative effects on offspring fitness, apparent inbreeding preference has been reported in a growing number of systems, including those with documented inbreeding depression. Here, we examined evidence for inbreeding depression and inbreeding preference in two populations (Clinton, New York and Davis, California, USA) of the cooperatively breeding American crow (Corvus brachyrhynchos). We then compared observed inbreeding strategies with theoretical expectations for optimal, adaptive levels of inbreeding, given the inclusive fitness benefits and population-specific magnitude of inbreeding depression. We found that low heterozygosity at a panel of 33 microsatellite markers was associated with low survival probability (fledging success) and low white blood cell counts among offspring in both populations. Despite these costs, our data were more consistent with inbreeding preference than avoidance: the observed heterozygosity among 396 sampled crow offspring was significantly lower than expected if local adults were mating by random chance. This pattern was consistent across a range of spatial scales in both populations. Theoretically adaptive levels of inbreeding, given the magnitude of inbreeding depression, were predicted to be very low in the California population, whereas complete disassociative mating was predicted in the New York population. Sexual conflict might have contributed to the apparent absence of inbreeding avoidance in crows. These data add to an increasing number of examples of an "inbreeding paradox," where inbreeding appears to be preferred despite inbreeding depression. This article is protected by copyright. All rights reserved.},
}
@article {pmid30210320,
year = {2018},
author = {Neupert, S and Hornung, M and Grenwille Millar, J and Kleineidam, CJ},
title = {Learning Distinct Chemical Labels of Nestmates in Ants.},
journal = {Frontiers in behavioral neuroscience},
volume = {12},
number = {},
pages = {191},
doi = {10.3389/fnbeh.2018.00191},
pmid = {30210320},
issn = {1662-5153},
abstract = {Colony coherence is essential for eusocial insects because it supports the inclusive fitness of colony members. Ants quickly and reliably recognize who belongs to the colony (nestmates) and who is an outsider (non-nestmates) based on chemical recognition cues (cuticular hydrocarbons: CHCs) which as a whole constitute a chemical label. The process of nestmate recognition often is described as matching a neural template with the label. In this study, we tested the prevailing view that ants use commonalities in the colony odor that are present in the CHC profile of all individuals of a colony or whether different CHC profiles are learned independently. We created and manipulated sub-colonies by adding one or two different hydrocarbons that were not present in the original colony odor of our Camponotus floridanus colony and later tested workers of the sub-colonies in one-on-one encounters for aggressive responses. We found that workers adjust their nestmate recognition by learning novel, manipulated CHC profiles, but still accept workers with the previous CHC profile. Workers from a sub-colony with two additional components showed aggression against workers with only one of the two components added to their CHC profile. Thus, additional components as well as the lack of a component can alter a label as "non-nestmate." Our results suggest that ants have multiple-templates to recognize nestmates carrying distinct labels. This finding is in contrast to what previously has been proposed, i.e., a widening of the acceptance range of one template. We conclude that nestmate recognition in ants is a partitioned (multiple-template) process of the olfactory system that allows discrimination and categorization of nestmates by differences in their CHC profiles. Our findings have strong implications for our understanding of the underlying mechanisms of colony coherence and task allocation because they illustrate the importance of individual experience and task associated differences in the CHC profiles that can be instructive for the organization of insect societies.},
}
@article {pmid30209226,
year = {2018},
author = {Kazem, AJN and Barth, Y and Pfefferle, D and Kulik, L and Widdig, A},
title = {Parent-offspring facial resemblance increases with age in rhesus macaques.},
journal = {Proceedings. Biological sciences},
volume = {285},
number = {1886},
pages = {},
doi = {10.1098/rspb.2018.1208},
pmid = {30209226},
issn = {1471-2954},
abstract = {Kin recognition is a key ability which facilitates the acquisition of inclusive fitness benefits and enables optimal outbreeding. In primates, phenotype matching is considered particularly important for the recognition of patrilineal relatives, as information on paternity is unlikely to be available via social familiarity. Phenotypic cues to both paternal and maternal relatedness exist in the facial features of humans and other primates. However, theoretical models suggest that in systems with uncertainty parentage it may be adaptive for offspring to conceal such cues when young, in order to avoid potential costs of being discriminated against by unrelated adults. Using experienced human raters, we demonstrate in a computer-based task that detection of parent-offspring resemblances in the faces of rhesus macaques (Macaca mulatta) increases significantly with offspring age. Moreover, this effect is specific to information about kinship, as raters were extremely successful at discriminating individuals even among the youngest animals. To our knowledge, this is the first evidence in non-humans for the age-dependent expression of visual cues used in kin recognition.},
}
@article {pmid30165602,
year = {2018},
author = {Bawa, KS and Ingty, T and Revell, LJ and Shivaprakash, KN},
title = {Correlated evolution of flower size and seed number in flowering plants (monocotyledons).},
journal = {Annals of botany},
volume = {},
number = {},
pages = {},
doi = {10.1093/aob/mcy154},
pmid = {30165602},
issn = {1095-8290},
abstract = {Background and Aims: Kin selection theory predicts that a parent may minimize deleterious effects of competition among seeds developing within ovaries by increasing the genetic relatedness of seeds within an ovary. Alternatively, the number of developing seeds could be reduced to one or a few. It has also been suggested that single or few seeded fruits may be correlated with small flowers, and multi-ovulate ovaries or many seeded fruits may be associated with large flowers with specialized pollination mechanisms. We examined the correlation between flower size and seed number in 69 families of monocotyledons to assess if correlations are significant and independent of phylogeny.

Methods: We first examined the effect of phylogenetic history on the evolution of these two traits, flower size and seed number, and then mapped correlations between them on the latest phylogenetic tree of monocotyledons.

Results: The results provide phylogenetically robust evidence of strong correlated evolution between flower size and seed number and show that correlated evolution of traits is not constrained by phylogenetic history of taxa. Moreover, the two character combinations, small flowers and a single or few seeds per fruit, and large flowers and many seeded fruits, have persisted in monocotyledons longer than other trait combinations.

Conclusions: The analyses support the suggestion that most angiosperms may fall into two categories, one with large flowers and many seeded fruits and the other with small flowers and single or few seeded fruits, and kin selection within ovaries may explain the observed patterns.},
}
@article {pmid30135160,
year = {2018},
author = {Downing, PA and Griffin, AS and Cornwallis, CK},
title = {Sex differences in helping effort reveal the effect of future reproduction on cooperative behaviour in birds.},
journal = {Proceedings. Biological sciences},
volume = {285},
number = {1885},
pages = {},
doi = {10.1098/rspb.2018.1164},
pmid = {30135160},
issn = {1471-2954},
abstract = {The evolution of helping behaviour in species that breed cooperatively in family groups is typically attributed to kin selection alone. However, in many species, helpers go on to inherit breeding positions in their natal groups, but the extent to which this contributes to selection for helping is unclear as the future reproductive success of helpers is often unknown. To quantify the role of future reproduction in the evolution of helping, we compared the helping effort of female and male retained offspring across cooperative birds. The kin selected benefits of helping are equivalent between female and male helpers-they are equally related to the younger siblings they help raise-but the future reproductive benefits of helping differ because of sex differences in the likelihood of breeding in the natal group. We found that the sex which is more likely to breed in its natal group invests more in helping, suggesting that in addition to kin selection, helping in family groups is shaped by future reproduction.},
}
@article {pmid30108624,
year = {2018},
author = {Ren, Y and Huang, K and Guo, S and Pan, R and Derek, DW and Qi, X and Wang, X and Wang, C and Zhao, H and Yang, B and Li, F and Li, B},
title = {Kinship promotes affiliative behaviors in a monkey.},
journal = {Current zoology},
volume = {64},
number = {4},
pages = {441-447},
doi = {10.1093/cz/zox046},
pmid = {30108624},
issn = {1674-5507},
abstract = {In social mammals, kinship is an important factor that often affects the interactions among individuals within groups. In primates that live in a multilevel society, kinship may affect affiliative patterns between individuals at different scales within the larger group. For this study, we use field observations and molecular methods to reveal the profiles of how kinship affects affiliative behaviors between individuals in a breeding band of wild golden snub-nosed monkeys (Rhinopithecus roxellana). We use a novel nonparametric test, the partition Mantel test, to measure independently the correlation between kinship and each of three affiliative behaviors. Our results show that more closely related females are more likely to groom each other. Average relatedness between adult females within the same one-male unit (OMU) is higher than that between adult females from different OMUs. We suggest that closely related females may reside in the same OMU in order to attain inclusive fitness benefits, and that kinship plays an important role in maintaining the social structure of this species.},
}
@article {pmid30080237,
year = {2018},
author = {D'Aloia, CC and Neubert, MG},
title = {The formation of marine kin structure: effects of dispersal, larval cohesion, and variable reproductive success.},
journal = {Ecology},
volume = {99},
number = {10},
pages = {2374-2384},
doi = {10.1002/ecy.2480},
pmid = {30080237},
issn = {0012-9658},
support = {DEB-1558904//US NSF/ ; },
abstract = {The spatial distribution of relatives has profound effects on kin interactions, inbreeding, and inclusive fitness. Yet, in the marine environment, the processes that generate patterns of kin structure remain understudied because larval dispersal on ocean currents was historically assumed to disrupt kin associations. Recent genetic evidence of co-occurring siblings challenges this assumption and raises the intriguing question of how siblings are found together after a (potentially) disruptive larval phase. Here, we develop individual-based models to explore how stochastic processes operating at the individual level affect expected kinship at equilibrium. Specifically, we predict how limited dispersal, sibling cohesion, and variability in reproductive success differentially affect patterns of kin structure. All three mechanisms increase mean kinship within populations, but their spatial effects are markedly different. We find that (1) when dispersal is limited, kinship declines monotonically as a function of the distance between individuals; (2) when siblings disperse cohesively, kinship increases within a site relative to between sites; and (3) when reproductive success varies, kinship increases equally at all distances. The differential effects of these processes therefore only become apparent when individuals are sampled at multiple spatial scales. Notably, our models suggest that aggregative larval behaviors, such as sibling cohesion, are not necessary to explain documented levels of relatedness within marine populations. Together, these findings establish a theoretical framework for disentangling the drivers of marine kin structure.},
}
@article {pmid30073752,
year = {2018},
author = {Andersson, M and Åhlund, M and Waldeck, P},
title = {Brood parasitism, relatedness and sociality: a kinship role in female reproductive tactics.},
journal = {Biological reviews of the Cambridge Philosophical Society},
volume = {},
number = {},
pages = {},
doi = {10.1111/brv.12455},
pmid = {30073752},
issn = {1469-185X},
abstract = {Conspecific brood parasitism (CBP) is a reproductive tactic in which parasitic females lay eggs in nests of other females of the same species that then raise the joint brood. Parasites benefit by increased reproduction, without costs of parental care for the parasitic eggs. CBP occurs in many egg-laying animals, among birds most often in species with large clutches and self-feeding young: two major factors facilitating successful parasitism. CBP is particularly common in waterfowl (Anatidae), a group with female-biased natal philopatry and locally related females. Theory suggests that relatedness between host and parasite can lead to inclusive fitness benefits for both, but if host costs are high, parasites should instead target unrelated females. Pairwise relatedness (r) in host-parasite (h-p) pairs of females has been estimated using molecular genetic methods in seven waterfowl (10 studies). In many h-p pairs, the two females were unrelated (with low r, near the local population mean). However, close relatives (r = 0.5) were over-represented in h-p pairs, which in all 10 studies had higher mean relatedness than other females. In one species where this was studied, h-p relatedness was higher than between nesting close neighbours, and hosts parasitized by non-relatives aggressively rejected other females. In another species, birth nest-mates (mother-daughters, sisters) associated in the breeding area as adults, and became h-p pairs more often than expected by chance. These and other results point to recognition of birth nest-mates and perhaps other close relatives. For small to medium host clutch sizes, addition of a few parasitic eggs need not reduce host offspring success. Estimates in two species suggest that hosts can then gain inclusive fitness if parasitized by relatives. Other evidence of female cooperation is incubation by old eider Somateria mollissima females of clutches laid by their relatives, and merging and joint care of broods of young. Merging females tended to be more closely related. Eiders associate with kin in many situations, and in some geese and swans, related females may associate over many years. Recent genetic evidence shows that also New World quails (Odontophoridae) have female-biased natal philopatry, CBP and brood merging, inviting further study and comparison with waterfowl. Kin-related parasitism also occurs in some insects, with revealing parallels and differences compared to birds. In hemipteran bugs, receiving extra eggs is beneficial for hosts by diluting offspring predation. In eggplant lace bugs Gargaphia solani, host and parasite are closely related, and kin selection favours egg donation to related females. Further studies of kinship in CBP, brood merging and other contexts can test if some of these species are socially more advanced than presently known.},
}
@article {pmid30059691,
year = {2018},
author = {Gleichsner, AM and Reinhart, K and Minchella, DJ},
title = {Of mice and worms: are co-infections with unrelated parasite strains more damaging to definitive hosts?.},
journal = {International journal for parasitology},
volume = {48},
number = {11},
pages = {881-885},
doi = {10.1016/j.ijpara.2018.05.004},
pmid = {30059691},
issn = {1879-0135},
abstract = {Intraspecific competition between co-infecting parasites can influence the amount of virulence, or damage, they do to their host. Kin selection theory dictates that infections with related parasite individuals should have lower virulence than infections with unrelated individuals, because they benefit from inclusive fitness and increased host longevity. These predictions have been tested in a variety of microparasite systems, and in larval stage macroparasites within intermediate hosts, but the influence of adult macroparasite relatedness on virulence has not been investigated in definitive hosts. This study used the human parasite Schistosoma mansoni to determine whether definitive hosts infected with related parasites experience lower virulence than hosts infected with unrelated parasites, and to compare the results from intermediate host studies in this system. The presence of unrelated parasites in an infection decreased parasite infectivity, the ability of a parasite to infect a definitive host, and total worm establishment in hosts, impacting the less virulent parasite strain more severely. Unrelated parasite co-infections had similar virulence to the more virulent of the two parasite strains. We combine these findings with complementary studies of the intermediate snail host and describe trade-offs in virulence and selection within the life cycle. Damage to the host by the dominant strain was muted by the presence of a competitor in the intermediate host, but was largely unaffected in the definitive host. Our results in this host-parasite system suggest that unrelated infections may select for higher virulence in definitive hosts while selecting for lower virulence in intermediate hosts.},
}
@article {pmid30055104,
year = {2018},
author = {Espinosa, A and Paz-Y-Miño-C, G},
title = {Discrimination Experiments in Entamoeba and Evidence from Other Protists Suggest Pathogenic Amebas Cooperate with Kin to Colonize Hosts and Deter Rivals.},
journal = {The Journal of eukaryotic microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jeu.12673},
pmid = {30055104},
issn = {1550-7408},
support = {P20 GM103430/GM/NIGMS NIH HHS/United States ; },
abstract = {Entamoeba histolytica is one of the least understood protists in terms of taxa, clone, and kin discrimination/recognition ability. However, the capacity to tell apart same or self (clone/kin) from different or nonself (nonclone/nonkin) has long been demonstrated in pathogenic eukaryotes like Trypanosoma and Plasmodium, free-living social amebas (Dictyostelium, Polysphondylium), budding yeast (Saccharomyces), and in numerous bacteria and archaea (prokaryotes). Kin discrimination/recognition is explained under inclusive fitness theory; that is, the reproductive advantage that genetically closely related organisms (kin) can gain by cooperating preferably with one another (rather than with distantly related or unrelated individuals), minimizing antagonism and competition with kin, and excluding genetic strangers (or cheaters = noncooperators that benefit from others' investments in altruistic cooperation). In this review, we rely on the outcomes of in vitro pairwise discrimination/recognition encounters between seven Entamoeba lineages to discuss the biological significance of taxa, clone, and kin discrimination/recognition in a range of generalist and specialist species (close or distantly related phylogenetically). We then focus our discussion on the importance of these laboratory observations for E. histolytica's life cycle, host infestation, and implications of these features of the amebas' natural history for human health (including mitigation of amebiasis).},
}
@article {pmid29998471,
year = {2018},
author = {Minorsky, PV},
title = {The functions of foliar nyctinasty: a review and hypothesis.},
journal = {Biological reviews of the Cambridge Philosophical Society},
volume = {},
number = {},
pages = {},
doi = {10.1111/brv.12444},
pmid = {29998471},
issn = {1469-185X},
abstract = {Foliar nyctinasty is a plant behaviour characterised by a pronounced daily oscillation in leaf orientation. During the day, the blades of nyctinastic plant leaves (or leaflets) assume a more or less horizontal position that optimises their ability to capture sunlight for photosynthesis. At night, the positions that the leaf blades assume, regardless of whether they arise by rising, falling or twisting, are essentially vertical. Among the ideas put forth to explain the raison d'être of foliar nyctinasty are that it: (i) improves the temperature relations of plants; (ii) helps remove surface water from foliage; (iii) prevents the disruption of photoperiodism by moonlight; and (iv) directly discourages insect herbivory. After discussing these previous hypotheses, a novel tritrophic hypothesis is introduced that proposes that foliar nyctinasty constitutes an indirect plant defence against nocturnal herbivores. It is suggested that the reduction in physical clutter that follows from nocturnal leaf closure may increase the foraging success of many types of animals that prey upon or parasitise herbivores. Predators and parasitoids generally use some combination of visual, auditory or olfactory cues to detect prey. In terrestrial environments, it is hypothesised that the vertical orientation of the blades of nyctinastic plants at night would be especially beneficial to flying nocturnal predators (e.g. bats and owls) and parasitoids whose modus operandi is death from above. The movements of prey beneath a plant with vertically oriented foliage would be visually more obvious to gleaning or swooping predators under nocturnal or crepuscular conditions. Such predators could also detect sounds made by prey better without baffling layers of foliage overhead to damp and disperse the signal. Moreover, any volatiles released by the prey would diffuse more directly to the awaiting olfactory apparatus of the predators or parasitoids. In addition to facilitating the demise of herbivores by carnivores and parasitoids, foliar nyctinasty, much like the enhanced illumination of the full moon, may mitigate feeding by nocturnal herbivores by altering their foraging behaviour. Foliar nyctinasty could also provide a competitive advantage by encouraging herbivores, seeking more cover, to forage on or around non-nyctinastic species. As an added advantage, foliar nyctinasty, by decreasing the temperature between plants through its effects on re-radiation, may slow certain types of ectothermic herbivores making them more vulnerable to predation. Foliar nyctinasty also may not solely be a behavioural adaptation against folivores; by discouraging foraging by granivores, the inclusive fitness of nyctinastic plants may be increased.},
}
@article {pmid29943825,
year = {2018},
author = {Bovet, J and Raiber, E and Ren, W and Wang, C and Seabright, P},
title = {Parent-offspring conflict over mate choice: An experimental study in China.},
journal = {British journal of psychology (London, England : 1953)},
volume = {109},
number = {4},
pages = {674-693},
doi = {10.1111/bjop.12319},
pmid = {29943825},
issn = {2044-8295},
support = {71540032//National Natural Science Foundation of China/ ; //ANR - Labex IAST/ ; },
abstract = {Both parents and offspring have evolved mating preferences that enable them to select mates and children-in-law to maximize their inclusive fitness. The theory of parent-offspring conflict predicts that preferences for potential mates may differ between parents and offspring: individuals are expected to value biological quality more in their own mates than in their offspring's mates and to value investment potential more in their offspring's mates than in their own mates. We tested this hypothesis in China using a naturalistic 'marriage market' where parents actively search for marital partners for their offspring. Parents gather at a public park to advertise the characteristics of their adult children, looking for a potential son or daughter-in-law. We presented 589 parents and young adults from the city of Kunming (Yunnan, China) with hypothetical mating candidates varying in their levels of income (proxy for investment potential) and physical attractiveness (proxy for biological quality). We found some evidence of a parent-offspring conflict over mate choice, but only in the case of daughters, who evaluated physical attractiveness as more important than parents. We also found an effect of the mating candidate's sex, as physical attractiveness was deemed more valuable in a female potential mate by parents and offspring alike.},
}
@article {pmid29924339,
year = {2018},
author = {Piekarski, PK and Carpenter, JM and Lemmon, AR and Moriarty Lemmon, E and Sharanowski, BJ},
title = {Phylogenomic evidence overturns current conceptions of social evolution in wasps (Vespidae).},
journal = {Molecular biology and evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/molbev/msy124},
pmid = {29924339},
issn = {1537-1719},
abstract = {The hypothesis that eusociality originated once in Vespidae has shaped interpretation of social evolution for decades and has driven the supposition that preimaginal morphophysiological differences between castes were absent at the outset of eusociality. Many researchers also consider casteless nest-sharing an antecedent to eusociality. Together, these ideas endorse a stepwise progression of social evolution in wasps (solitary → casteless nest-sharing → eusociality with rudimentary behavioral castes → eusociality with preimaginal caste-biasing → morphologically differentiated castes). Here we infer the phylogeny of Vespidae using sequence data generated via anchored hybrid enrichment from 378 loci across 136 vespid species and perform ancestral state reconstructions to test whether rudimentary and monomorphic castes characterized the initial stages of eusocial evolution. Our results reject the single origin of eusociality hypothesis, contest the supposition that eusociality emerged from a casteless nest-sharing ancestor, and suggest that eusociality in Polistinae + Vespinae began with castes having morphological differences. An abrupt appearance of castes with ontogenetically established morphophysiological differences conflicts with the current conception of stepwise social evolution and suggests that the climb up the ladder of sociality does not occur through sequential mutation. Phenotypic plasticity and standing genetic variation could explain how cooperative brood care evolved in concert with nest-sharing and how morphologically dissimilar castes arose without a rudimentary intermediate. Furthermore, preimaginal caste-biasing at the outset of eusociality implicates a subsocial route to eusociality in Polistinae + Vespinae, emphasizing the role of mother-daughter interactions and subfertility (i.e. the cost component of kin selection) in the origin of workers.},
}
@article {pmid29904961,
year = {2018},
author = {Rodrigues, AMM},
title = {Demography, life history and the evolution of age-dependent social behaviour.},
journal = {Journal of evolutionary biology},
volume = {31},
number = {9},
pages = {1340-1353},
doi = {10.1111/jeb.13308},
pmid = {29904961},
issn = {1420-9101},
abstract = {Since the inception of modern social evolution theory, a vast majority of studies have sought to explain cooperation using relatedness-driven hypotheses. Natural populations, however, show a substantial amount of variation in social behaviour that is uncorrelated with relatedness. Age offers a major alternative explanation for variation in behaviour that remains unaccounted for. Most natural populations are structured into age-classes, with ageing being a nearly universal feature of most major taxa, including eukaryotic and prokaryotic organisms. Despite this, the theoretical underpinnings of age-dependent social behaviour remain limited. Here, I investigate how group age-composition, demography and life history shape trajectories of age-dependent behaviours that are expressed conditionally on an actor and recipient's age. I show that demography introduces novel age-dependent selective pressures acting on social phenotypes. Furthermore, I find that life history traits influence the costs and benefits of cooperation directly, but also indirectly. Life history has a strong impact not only on the genetic structure of the population but also on the distribution of group age-compositions, with both of these processes influencing the expression of age-dependent cooperation. Age of peak reproductive performance, in particular, is of chief importance for the evolution of cooperation, as this will largely determine the age and relatedness of social partners. Moreover, my results suggest that later-life reproductive senescence may occur because of demographic effects alone, which opens new vistas on the evolution of menopause and related phenomena.},
}
@article {pmid29892408,
year = {2018},
author = {Davies, NG and Gardner, A},
title = {Monogamy promotes altruistic sterility in insect societies.},
journal = {Royal Society open science},
volume = {5},
number = {5},
pages = {172190},
doi = {10.1098/rsos.172190},
pmid = {29892408},
issn = {2054-5703},
abstract = {Monogamy is associated with sibling-directed altruism in multiple animal taxa, including insects, birds and mammals. Inclusive-fitness theory readily explains this pattern by identifying high relatedness as a promoter of altruism. In keeping with this prediction, monogamy should promote the evolution of voluntary sterility in insect societies if sterile workers make for better helpers. However, a recent mathematical population-genetics analysis failed to identify a consistent effect of monogamy on voluntary worker sterility. Here, we revisit that analysis. First, we relax genetic assumptions, considering not only alleles of extreme effect-encoding either no sterility or complete sterility-but also alleles with intermediate effects on worker sterility. Second, we broaden the stability analysis-which focused on the invasibility of populations where either all workers are fully sterile or all workers are fully reproductive-to identify where intermediate pure or mixed evolutionarily stable states may occur. Third, we consider a broader range of demographically explicit ecological scenarios relevant to altruistic worker non-reproduction and to the evolution of eusociality more generally. We find that, in the absence of genetic constraints, monogamy always promotes altruistic worker sterility and may inhibit spiteful worker sterility. Our extended analysis demonstrates that an exact population-genetics approach strongly supports the prediction of inclusive-fitness theory that monogamy promotes sib-directed altruism in social insects.},
}
@article {pmid29848655,
year = {2018},
author = {Dos Santos, M and West, SA},
title = {The coevolution of cooperation and cognition in humans.},
journal = {Proceedings. Biological sciences},
volume = {285},
number = {1879},
pages = {},
doi = {10.1098/rspb.2018.0723},
pmid = {29848655},
issn = {1471-2954},
abstract = {Cooperative behaviours in archaic hunter-gatherers could have been maintained partly due to the gains from cooperation being shared with kin. However, the question arises as to how cooperation was maintained after early humans transitioned to larger groups of unrelated individuals. We hypothesize that after cooperation had evolved via benefits to kin, the consecutive evolution of cognition increased the returns from cooperating, to the point where benefits to self were sufficient for cooperation to remain stable when group size increased and relatedness decreased. We investigate the theoretical plausibility of this hypothesis, with both analytical modelling and simulations. We examine situations where cognition either (i) increases the benefits of cooperation, (ii) leads to synergistic benefits between cognitively enhanced cooperators, (iii) allows the exploitation of less intelligent partners, and (iv) the combination of these effects. We find that cooperation and cognition can coevolve-cooperation initially evolves, favouring enhanced cognition, which favours enhanced cooperation, and stabilizes cooperation against a drop in relatedness. These results suggest that enhanced cognition could have transformed the nature of cooperative dilemmas faced by early humans, thereby explaining the maintenance of cooperation between unrelated partners.},
}
@article {pmid29802804,
year = {2018},
author = {Wade, MJ and Fitzpatrick, CL and Lively, CM},
title = {50-year anniversary of Lloyd's "mean crowding": Ideas on patchy distributions.},
journal = {The Journal of animal ecology},
volume = {87},
number = {5},
pages = {1221-1226},
doi = {10.1111/1365-2656.12854},
pmid = {29802804},
issn = {1365-2656},
abstract = {This year marks the 50th anniversary of Monte B. Lloyd's "Mean Crowding" (1967) paper, in which he introduced a metric that accounts for an individual's experience of conspecific density. Mean crowding allows ecologists to measure the degree of spatial aggregation of individuals in a manner relevant to intraspecific competition for resources. We take the concept of mean crowding a step beyond its most common usage and that it has a mathematical relationship to many of the most important concepts in ecology and evolutionary biology. Mean crowding, a first-order approximation of the degree of nonrandomness in a distribution, can function as a powerful heuristic that can unify concepts across disciplines in a more general way that Lloyd originally envisioned.},
}
@article {pmid29797146,
year = {2018},
author = {Nila, S and Barthes, J and Crochet, PA and Suryobroto, B and Raymond, M},
title = {Kin Selection and Male Homosexual Preference in Indonesia.},
journal = {Archives of sexual behavior},
volume = {47},
number = {8},
pages = {2455-2465},
doi = {10.1007/s10508-018-1202-y},
pmid = {29797146},
issn = {1573-2800},
support = {HUMANWAY ANR-12- BSV7-0008-01//Agence Nationale pour la Recherche (ANR)/ ; UMR CNRS 5554//Institut des Sciences de l'Évolution de Montpellier/ ; },
abstract = {Male homosexual preference (MHP) challenges evolutionary thinking because the preference for male-male relationships is heritable, implies a fertility cost (lower offspring number), and is relatively frequent in some societies (2-6% in Western countries) for a costly trait. It has been proposed that individuals with a MHP counterbalance reproductive costs through the transfer of resources to kin, thereby improving their indirect reproduction through kin's reproductive success. This kin selection hypothesis is not supported in Western countries and Japan, although consistent evidence has been obtained in Samoa. In this study, data from Java (Indonesia) were obtained to assess the avuncular tendencies of men with contrasting sexual orientation to measure possible resource transfer. Consistent with the kin selection hypothesis, males with a homosexual orientation reported an increased willingness to transfer resources toward nephews and nieces and declared having transferred more money to nephews and nieces. We developed a method to quantitatively estimate the contribution of kin selection on inclusive reproduction associated to sexual orientation, taking into account various possible biases. Kin selection reduced the direct reproductive cost of homosexual men by 20%, so suggesting that kin selection alone is insufficient to explain the maintenance of male homosexuality. Other potential factors are discussed, as well as the limitations of the study and the social determinant operating for the expression of increased avuncular tendencies of homosexual men.},
}
@article {pmid29792446,
year = {2018},
author = {Lang, SF and Fowers, BJ},
title = {An expanded theory of Alzheimer's caregiving.},
journal = {The American psychologist},
volume = {},
number = {},
pages = {},
doi = {10.1037/amp0000323},
pmid = {29792446},
issn = {1935-990X},
abstract = {The ancient and cross-culturally prevalent pattern of caregiving suggests that long-term caregiving is species characteristic for humans. If so, then an evolutionary account of the adaptation(s) that underwrite this caregiving is necessary, particularly for the one-sided and long-term nature of Alzheimer's caregiving. Four standard evolutionary explanations are evaluated: kin selection theory, the grandmother hypothesis, direct reciprocity, and indirect reciprocity. Each is found inadequate to explain caregiving because of the lack of reproductive benefits. These evolutionary accounts also assume that relationships are only valuable to the degree that they provide benefits and that relationship partners are predominantly motivated by self-interest. Attachment provides another explanation, which evolved initially to ensure infant protection and nurturance, but was exapted for important adult relationships. Attachment relationships naturally include caregiving and engender long-term relational commitment. Yet attachment theory is ambiguous about whether relationships are maintained for the sake of security benefits or because they have inherent value. This ambiguity undermines the explanatory value of attachment theory for Alzheimer's caregiving. Therefore, a shared identity theory is offered that highlights the inherent value of the relationship and the loved one, transcending the predominant focus on beneficial individual outcomes. The theory emphasizes the frequent human motivation to benefit others because of their mutual commitment, shared identity, and shared goals. The conclusion is that fully understanding and supporting the arduous efforts of caregiving for loved ones with Alzheimer's requires psychologists to fully appreciate and support the deep and meaningful motivations that often inspire the humanity seen in caregiving. (PsycINFO Database Record},
}
@article {pmid29765670,
year = {2018},
author = {Koster, J},
title = {Family ties: the multilevel effects of households and kinship on the networks of individuals.},
journal = {Royal Society open science},
volume = {5},
number = {4},
pages = {172159},
doi = {10.1098/rsos.172159},
pmid = {29765670},
issn = {2054-5703},
abstract = {Among social mammals, humans uniquely organize themselves into communities of households that are centred around enduring, predominantly monogamous unions of men and women. As a consequence of this social organization, individuals maintain social relationships both within and across households, and potentially there is conflict among household members about which social ties to prioritize or de-emphasize. Extending the logic of structural balance theory, I predict that there will be considerable overlap in the social networks of individual household members, resulting in a pattern of group-level reciprocity. To test this prediction, I advance the Group-Structured Social Relations Model, a generalized linear mixed model that tests for group-level effects in the inter-household social networks of individuals. The empirical data stem from social support interviews conducted in a community of indigenous Nicaraguan horticulturalists, and model results show high group-level reciprocity among households. Although support networks are organized around kinship, covariates that test predictions of kin selection models do not receive strong support, potentially because most kin-directed altruism occurs within households, not between households. In addition, the models show that households with high genetic relatedness in part from children born to adulterous relationships are less likely to assist each other.},
}
@article {pmid29756687,
year = {2018},
author = {Jänig, S and Weiß, BM and Widdig, A},
title = {Comparing the sniffing behavior of great apes.},
journal = {American journal of primatology},
volume = {80},
number = {6},
pages = {e22872},
doi = {10.1002/ajp.22872},
pmid = {29756687},
issn = {1098-2345},
abstract = {The importance of smell in humans is well established but we know little about it in regard to our closest relatives, the great apes, as systematic studies on their olfactory behavior are still lacking. Olfaction has long been considered to be of lesser importance in hominids given their relatively smaller olfactory bulbs, fewer functional olfactory receptor genes than other species and absence of a functional vomeronasal organ. Therefore, the aim of this study was to evaluate the use of olfaction in hominids. In particular, we observed sniffing behavior in captive groups of four species (Sumatran orangutans, Pongo abelii; Western lowland gorillas, Gorilla gorilla gorilla; Western chimpanzees, Pan troglodytes verus; bonobos, Pan paniscus) and evaluated in which contexts sniffing was used. Our results show that all investigated species frequently used the sense of smell, and that the sniffing frequency varied with species, sex, age, and context. Most sniffing events were observed in gorillas in comparison to the three other species. Sniffing frequencies were also influenced by sex, with males sniffing slightly more often than females. Furthermore, our results revealed an effect of age, with younger individuals sniffing more often than older individuals. All species mainly sniffed in the non-social context (i.e., toward food and other environmental items) rather than in the social context (i.e., at conspecifics), suggesting that the evaluation of the environment and the nutritional value of food items is of major importance to all great ape species investigated here. In contrast to the other species and female chimpanzees, however, male chimpanzees most often used olfaction to inspect their conspecifics. Together, our study suggests that olfaction is likely to be more important in great apes than previously appreciated.},
}
@article {pmid29753459,
year = {2018},
author = {Boose, K and White, F and Brand, C and Meinelt, A and Snodgrass, J},
title = {Infant handling in bonobos (Pan paniscus): Exploring functional hypotheses and the relationship to oxytocin.},
journal = {Physiology & behavior},
volume = {193},
number = {Pt A},
pages = {154-166},
doi = {10.1016/j.physbeh.2018.04.012},
pmid = {29753459},
issn = {1873-507X},
abstract = {Infant handling describes interactions between infants and non-maternal group members and is widespread across mammalian taxa. The expression of infant handling behaviors, defined as any affiliative or agonistic interaction between a group member and an infant, varies considerably among primate species. Several functional hypotheses may explain the adaptive value of infant handling including the Kin Selection hypothesis, which describes handling as a mechanism through which indirect fitness is increased and predicts a bias in handling behaviors directed toward related (genetic) infants; the Alliance Formation hypothesis, which describes handling as a social commodity and predicts females with infants will support handlers during conflict; and the Learning-to-Mother hypothesis, which describes handling as a mechanism through which handlers learn species-specific maternal behaviors and predicts that handling will occur most frequently in immature and nulliparous females. Using behavioral observation and data on urinary oxytocin, a neuropeptide hormone known to modulate maternal care and social bonds in mammals, the purpose of this study was to describe the pattern of infant handling in bonobos (Pan paniscus) and to explore proposed functional hypotheses. Data show that related infant-handler dyads occurred significantly more frequently than unrelated infant-handler dyads during some of the study period and that handling was positively correlated with support during conflict. Data also showed that immature and nulliparous females handled infants significantly more than other age-sex categories and exhibited higher post handling oxytocin values than other age-sex class. The trends identified in this data set provide insight into the role oxytocin may play in facilitating care-giving behaviors in young female bonobos and help to narrow the focus of future research efforts, particularly those associated with the Kin Selection, Alliance Formation, and Learning-to-Mother functional hypotheses.},
}
@article {pmid29745213,
year = {2017},
author = {Lai, BM and Wang, MZ and Shen, DS},
title = {[Bacterial quorum sensing: Cooperation and cheating].},
journal = {Ying yong sheng tai xue bao = The journal of applied ecology},
volume = {28},
number = {5},
pages = {1735-1742},
doi = {10.13287/j.1001-9332.201705.018},
pmid = {29745213},
issn = {1001-9332},
mesh = {*Bacteria ; Biofilms ; Ecological and Environmental Phenomena ; *Quorum Sensing ; },
abstract = {Quorum sensing (QS), a cell-to-cell communication, regulates a variety of social beha-viors, such as biofilm formation, public goods produce and gene horizontal transfer of bacteria. In the process of quorum sensing, public goods could be utilized by any members in the population, which was termed as cooperation. Notably, public goods also could be shared by the individuals who could not produce them, which was termed as cheating. Once cheaters come up, they possibly maintain equilibrium with cooperators, meanwhile they also possibly induce the collapse of population due to their rapid growth and shortage of public goods. Therefore, invasion of cheaters arouses wide attentions in medicine, agriculture, food science and so on regarded as a new strategy to control pathogens. In this study, based on the introduction about the theory of bacterial quorum sensing cooperation and cheating, we analyzed the factors influencing the formation and development of the relationship between cooperator and cheater. Moreover, we discussed the mechanism of stabilization in the relationship between cooperator and cheater, including kin selection, metabolic prudence, metabolic constraint (gene pleiotropy) and policing quorum sensing. Finally, some problems in current researches of quorum sensing cooperation and cheating were presented as well as the future research directions. We hoped this paper could deepen the understanding of bacterial quorum sen-sing and ecology of bacterial population.},
}
@article {pmid29735672,
year = {2018},
author = {Madgwick, PG and Stewart, B and Belcher, LJ and Thompson, CRL and Wolf, JB},
title = {Strategic investment explains patterns of cooperation and cheating in a microbe.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {115},
number = {21},
pages = {E4823-E4832},
doi = {10.1073/pnas.1716087115},
pmid = {29735672},
issn = {1091-6490},
support = {//Wellcome Trust/United Kingdom ; BB/M01035X/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M007146/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; WT095643AIA//Wellcome Trust/United Kingdom ; },
mesh = {*Biological Evolution ; *Cooperative Behavior ; Dictyostelium/*physiology ; *Game Theory ; Individuality ; *Models, Biological ; Spores, Protozoan/*physiology ; },
abstract = {Contributing to cooperation is typically costly, while its rewards are often available to all members of a social group. So why should individuals be willing to pay these costs, especially if they could cheat by exploiting the investments of others? Kin selection theory broadly predicts that individuals should invest more into cooperation if their relatedness to group members is high (assuming they can discriminate kin from nonkin). To better understand how relatedness affects cooperation, we derived the ‟Collective Investment" game, which provides quantitative predictions for patterns of strategic investment depending on the level of relatedness. We then tested these predictions by experimentally manipulating relatedness (genotype frequencies) in mixed cooperative aggregations of the social amoeba Dictyostelium discoideum, which builds a stalk to facilitate spore dispersal. Measurements of stalk investment by natural strains correspond to the predicted patterns of relatedness-dependent strategic investment, wherein investment by a strain increases with its relatedness to the group. Furthermore, if overall group relatedness is relatively low (i.e., no strain is at high frequency in a group) strains face a scenario akin to the "Prisoner's Dilemma" and suffer from insufficient collective investment. We find that strains employ relatedness-dependent segregation to avoid these pernicious conditions. These findings demonstrate that simple organisms like D. discoideum are not restricted to being ‟cheaters" or ‟cooperators" but instead measure their relatedness to their group and strategically modulate their investment into cooperation accordingly. Consequently, all individuals will sometimes appear to cooperate and sometimes cheat due to the dynamics of strategic investing.},
}
@article {pmid29734799,
year = {2018},
author = {Peters, K and Worrich, A and Weinhold, A and Alka, O and Balcke, G and Birkemeyer, C and Bruelheide, H and Calf, OW and Dietz, S and Dührkop, K and Gaquerel, E and Heinig, U and Kücklich, M and Macel, M and Müller, C and Poeschl, Y and Pohnert, G and Ristok, C and Rodríguez, VM and Ruttkies, C and Schuman, M and Schweiger, R and Shahaf, N and Steinbeck, C and Tortosa, M and Treutler, H and Ueberschaar, N and Velasco, P and Weiß, BM and Widdig, A and Neumann, S and Dam, NMV},
title = {Current Challenges in Plant Eco-Metabolomics.},
journal = {International journal of molecular sciences},
volume = {19},
number = {5},
pages = {},
doi = {10.3390/ijms19051385},
pmid = {29734799},
issn = {1422-0067},
mesh = {*Ecology ; Metabolomics/*trends ; Plants/*genetics/metabolism ; },
abstract = {The relatively new research discipline of Eco-Metabolomics is the application of metabolomics techniques to ecology with the aim to characterise biochemical interactions of organisms across different spatial and temporal scales. Metabolomics is an untargeted biochemical approach to measure many thousands of metabolites in different species, including plants and animals. Changes in metabolite concentrations can provide mechanistic evidence for biochemical processes that are relevant at ecological scales. These include physiological, phenotypic and morphological responses of plants and communities to environmental changes and also interactions with other organisms. Traditionally, research in biochemistry and ecology comes from two different directions and is performed at distinct spatiotemporal scales. Biochemical studies most often focus on intrinsic processes in individuals at physiological and cellular scales. Generally, they take a bottom-up approach scaling up cellular processes from spatiotemporally fine to coarser scales. Ecological studies usually focus on extrinsic processes acting upon organisms at population and community scales and typically study top-down and bottom-up processes in combination. Eco-Metabolomics is a transdisciplinary research discipline that links biochemistry and ecology and connects the distinct spatiotemporal scales. In this review, we focus on approaches to study chemical and biochemical interactions of plants at various ecological levels, mainly plant⁻organismal interactions, and discuss related examples from other domains. We present recent developments and highlight advancements in Eco-Metabolomics over the last decade from various angles. We further address the five key challenges: (1) complex experimental designs and large variation of metabolite profiles; (2) feature extraction; (3) metabolite identification; (4) statistical analyses; and (5) bioinformatics software tools and workflows. The presented solutions to these challenges will advance connecting the distinct spatiotemporal scales and bridging biochemistry and ecology.},
}
@article {pmid29728393,
year = {2018},
author = {Bruger, EL and Waters, CM},
title = {Maximizing Growth Yield and Dispersal via Quorum Sensing Promotes Cooperation in Vibrio Bacteria.},
journal = {Applied and environmental microbiology},
volume = {84},
number = {14},
pages = {},
doi = {10.1128/AEM.00402-18},
pmid = {29728393},
issn = {1098-5336},
abstract = {Quorum sensing (QS) is a form of bacterial chemical communication that regulates cellular phenotypes, including certain cooperative behaviors, in response to environmental and demographic changes. Despite the existence of proposed mechanisms that stabilize QS against defector exploitation, it is unclear if or how QS cooperators can proliferate in some model systems in populations mostly consisting of defectors. We predicted that growth in fragmented subpopulations could allow QS cooperators to invade a QS defector population. This could occur despite cooperators having lower relative fitnesses than defectors due to favored weighting of genotypes that produce larger populations of bacteria. Mixed metapopulations of Vibrio QS-proficient or unconditional cooperators and QS defectors were diluted and fragmented into isolated subpopulations in an environment that requires QS-regulated public good production to achieve larger population yields. Under these conditions, we observed global invasions of both cooperator genotypes into populations composed of primarily defectors. This spatially dependent increase in cooperator frequency was replicated for QS cooperators when mixed populations were competed in soft agar motility plates under conditions that allowed cooperators to disperse and outcompete defectors at the population edge, despite being less motile in isolation than defectors. These competition results show that the coordinated growth and dispersal of QS cooperators to additional resources is heavily favored in comparison to unconditional cooperation, and that dispersal of cooperators by motility into new environments, examined here in laboratory populations, constitutes a key mechanism for maintaining QS-regulated cooperation in the face of defection.IMPORTANCE Behaviors that are cooperative in nature are at risk of exploitation by cheating and are thus difficult to maintain by natural selection alone. While bacterial cell-cell communication, known as quorum sensing (QS), can stabilize microbial cooperative behaviors and is widespread in Vibrio species, it is unclear how QS can increase the frequency of cooperative strains in the presence of defectors without additional mechanisms. In this study, we demonstrate under multiple conditions that QS-mediated cooperation can increase in populations of Vibrio strains when cells experience narrow population bottlenecks or disperse from defectors. This occurred for both conditional cooperation mediated by QS and for unconditional cooperation, although conditional cooperators were better able to stabilize cooperation over a much wider range of conditions. Thus, we observed that population structuring allowed for assortment of competing genotypes and promoted cooperation via kin selection in microbes in a QS-dependent manner.},
}
@article {pmid29717496,
year = {2018},
author = {Cords, M and Minich, T and Roberts, SJ and Sleator, C},
title = {Evidence for paternal kin bias in the social affiliation of adult female blue monkeys.},
journal = {American journal of primatology},
volume = {80},
number = {5},
pages = {e22761},
doi = {10.1002/ajp.22761},
pmid = {29717496},
issn = {1098-2345},
abstract = {If animals increase inclusive fitness by cooperating with relatives, nepotism should involve maternal and paternal kin equally, all else being equal. Evidence of a behavioral bias toward paternal half-siblings in primates is both limited and mixed, with most positive reports from papionins. To expand knowledge of paternal kin recognition, particularly in cercopithecine monkeys, we examined evidence for paternal kin bias in wild blue monkeys (Cercopithecus mitis), a species living mostly in one-male groups. Seasonal breeding and the amount of male reproductive skew in blue monkeys suggests that opportunities to distinguish paternal kin are plentiful, and their social system would make such discrimination beneficial. We compared spatial association and social contact (grooming and contact-sitting) of 20 adult females with at least one paternal half-sibling and at least one non-relative that were present at the same time. We used two data sets, one in which social partners were other parous females, the other in which they were juveniles. Data came from a 7-year period. When interacting with other adult females, subjects groomed and sat in contact with paternal half-siblings significantly more than with known non-kin, and there was a similar trend for spatial association. We detected no paternal kin bias in interactions with juvenile partners. Kin-biased affiliative contact with adult female partners did not appear to be based on age proximity, measured by birth cohort. The study species' social system suggests phenotype matching as the most likely alternative mechanism, though we could not test it directly. Across both behaviors, there was no significant relationship between the number of matrilineal kin a subject had and the degree to which she preferred paternal half-siblings over non-kin as affiliative partners. These findings contribute to a comparative understanding of paternal kin recognition in primates.},
}
@article {pmid29679501,
year = {2018},
author = {Rodrigues, AMM and Taylor, TB},
title = {Ecological and demographic correlates of cooperation from individual to budding dispersal.},
journal = {Journal of evolutionary biology},
volume = {31},
number = {7},
pages = {1058-1070},
doi = {10.1111/jeb.13286},
pmid = {29679501},
issn = {1420-9101},
abstract = {Identifying the ecological and demographic factors that promote the evolution of cooperation is a major challenge for evolutionary biologists. Explanations for the adaptive evolution of cooperation seek to determine which factors make reproduction in cooperative groups more favourable than independent breeding or other selfish strategies. A vast majority of the hypotheses posit that cooperative groups emerge in the context of philopatry, high costs of dispersal, high population density and environmental stability. This route to cooperation, however, fails to explain a growing body of empirical evidence in which cooperation is not associated with one or more of these predictors. We propose an alternative evolutionary path towards the emergence of cooperation that accounts for the disparities observed in the current literature. We find that when dispersal is mediated by a group mode of dispersal, commonly termed budding dispersal, our mathematical model reveals an association between cooperation and immigration, lower costs of dispersal, low population density and environmental variability. Furthermore, by studying the continuum from the individual to the partial and full budding mode of dispersal, we can explicitly explain why the correlates of cooperation change under budding. This enables us to outline a general model for the evolution of cooperation that accounts for a substantial amount of empirical evidence. Our results suggest that natural selection may have favoured two major contrasting pathways for the evolution of cooperation depending on a set of key ecological and demographic factors.},
}
@article {pmid29664006,
year = {2018},
author = {Jiang, W and Wei, Y and Long, Y and Owen, A and Wang, B and Wu, X and Luo, S and Dang, Y and Ma, DK},
title = {A genetic program mediates cold-warming response and promotes stress-induced phenoptosis in C. elegans.},
journal = {eLife},
volume = {7},
number = {},
pages = {},
doi = {10.7554/eLife.35037},
pmid = {29664006},
issn = {2050-084X},
support = {Post-doctoral fellowship//China Postdoctoral Science Foundation/ ; R01 AG032435/AG/NIA NIH HHS/United States ; R01 GM117461/GM/NIGMS NIH HHS/United States ; R00HL116654//National Heart, Lung, and Blood Institute/ ; R00 HL116654/HL/NHLBI NIH HHS/United States ; R01GM117461//National Institute of General Medical Sciences/ ; 1-16-IBS-197//American Diabetes Association/ ; R01AG032435//National Institute on Aging/ ; Fellowship in Science and Engineering//David and Lucile Packard Foundation/ ; Pew Scholar Award//Pew Charitable Trusts/ ; },
abstract = {How multicellular organisms respond to and are impacted by severe hypothermic stress is largely unknown. From C. elegans screens for mutants abnormally responding to cold-warming stimuli, we identify a molecular genetic pathway comprising ISY-1, a conserved uncharacterized protein, and ZIP-10, a bZIP-type transcription factor. ISY-1 gatekeeps the ZIP-10 transcriptional program by regulating the microRNA mir-60. Downstream of ISY-1 and mir-60, zip-10 levels rapidly and specifically increase upon transient cold-warming exposure. Prolonged zip-10 up-regulation induces several protease-encoding genes and promotes stress-induced organismic death, or phenoptosis, of C. elegans. zip-10 deficiency confers enhanced resistance to prolonged cold-warming stress, more prominently in adults than larvae. We conclude that the ZIP-10 genetic program mediates cold-warming response and may have evolved to promote wild-population kin selection under resource-limiting and thermal stress conditions.},
}
@article {pmid29657778,
year = {2018},
author = {Mattison, SM and Seabright, E and Reynolds, AZ and Cao, JB and Brown, MJ and Feldman, MW},
title = {Adopted daughters and adopted daughters-in-law in Taiwan: a mortality analysis.},
journal = {Royal Society open science},
volume = {5},
number = {3},
pages = {171745},
doi = {10.1098/rsos.171745},
pmid = {29657778},
issn = {2054-5703},
abstract = {Adoption is sometimes considered paradoxical from an evolutionary perspective because the costs spent supporting an adopted child would be better spent on rearing one's own. Kin selection theory is commonly used to solve this paradox, because the adoption of closely related kin contributes to the inclusive fitness of the adoptive parent. In this paper, we perform a novel test of kin selection theory in the context of adoption by asking whether adopted daughters-in-law, who contribute directly (i.e. genealogically) to the perpetuation of their adoptive families' lineages, experience lower mortality than daughters adopted for other purposes in historical Taiwan. We show that both classes of adopted daughter suffer lower mortality than biological daughters, but that the protective effect of adoption is stronger among daughters who were not adopted with the intention of perpetuating the family lineage. We speculate as to the possible benefits of such a pattern and emphasize the need to move beyond typological definitions of adoption to understand the specific costs and benefits involved in different forms of caring for others' children.},
}
@article {pmid29624797,
year = {2018},
author = {Yirmiya, K and Segal, NL and Bloch, G and Knafo-Noam, A},
title = {Prosocial and self-interested intra-twin pair behavior in monozygotic and dizygotic twins in the early to middle childhood transition.},
journal = {Developmental science},
volume = {21},
number = {6},
pages = {e12665},
doi = {10.1111/desc.12665},
pmid = {29624797},
issn = {1467-7687},
support = {//The Science of Generosity Initiative, funded by the Templeton Foundation/International ; 240994//European Research Council (ERC)/International ; },
abstract = {Several related and complementary theoretical frameworks have been proposed to explain the existence of prosocial behavior, despite its potential fitness cost to the individual. These include kin selection theory, proposing that organisms have a propensity to help those to whom they are genetically related, and reciprocity, referring to the benefit of being prosocial, depending on past and future mutual interactions. A useful paradigm to examine prosociality is to compare mean levels of this behavior between monozygotic (MZ) and dizygotic (DZ) twins. Here, we examined the performance of 883 6.5-year-old twins (139 MZ and 302 DZ same-sex 6.5-year-old full twin pairs) in the Differential Productivity Task. In this task, the twins' behaviors were observed under two conditions: working for themselves vs. working for their co-twin. There were no significant differences between the performances of MZ and DZ twins in the prosocial condition of the task. Correlations within the twin dyads were significantly higher in MZ than DZ twins in the self-interested condition. However, similar MZ and DZ correlations were found in the prosocial condition, supporting the role of reciprocity in twins' prosociality towards each other.},
}
@article {pmid29622934,
year = {2018},
author = {Bebbington, K and Fairfield, EA and Spurgin, LG and Kingma, SA and Dugdale, H and Komdeur, J and Richardson, DS},
title = {Joint care can outweigh costs of nonkin competition in communal breeders.},
journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology},
volume = {29},
number = {1},
pages = {169-178},
doi = {10.1093/beheco/arx137},
pmid = {29622934},
issn = {1045-2249},
abstract = {Competition between offspring can greatly influence offspring fitness and parental investment decisions, especially in communal breeders where unrelated competitors have less incentive to concede resources. Given the potential for escalated conflict, it remains unclear what mechanisms facilitate the evolution of communal breeding among unrelated females. Resolving this question requires simultaneous consideration of offspring in noncommunal and communal nurseries, but such comparisons are missing. In the Seychelles warbler Acrocephalus sechellensis, we compare nestling pairs from communal nests (2 mothers) and noncommunal nests (1 mother) with singleton nestlings. Our results indicate that increased provisioning rate can act as a mechanism to mitigate the costs of offspring rivalry among nonkin. Increased provisioning in communal broods, as a consequence of having 2 female parents, mitigates any elevated costs of offspring rivalry among nonkin: per-capita provisioning and survival was equal in communal broods and singletons, but lower in noncommunal broods. Individual offspring costs were also more divergent in noncommunal broods, likely because resource limitation exacerbates differences in competitive ability between nestlings. It is typically assumed that offspring rivalry among nonkin will be more costly because offspring are not driven by kin selection to concede resources to their competitors. Our findings are correlational and require further corroboration, but may help explain the evolutionary maintenance of communal breeding by providing a mechanism by which communal breeders can avoid these costs.},
}
@article {pmid29607032,
year = {2018},
author = {Mukai, H and Hironaka, M and Tojo, S and Nomakuchi, S},
title = {Maternal hatching synchronization in a subsocial burrower bug mitigates the risk of future sibling cannibalism.},
journal = {Ecology and evolution},
volume = {8},
number = {6},
pages = {3376-3381},
doi = {10.1002/ece3.3894},
pmid = {29607032},
issn = {2045-7758},
abstract = {Sibling cannibalism-the killing and consumption of conspecifics within broods-carries a high risk of direct and inclusive fitness loss for parents and offspring. We reported previously that a unique vibrational behavior shown by the mother of the subsocial burrower bug, Adomerus rotundus (Heteroptera: Cydnidae), induced synchronous hatching. Maternal regulation may be one of the most effective mechanisms for preventing or limiting sibling cannibalism. Here, we tested the hypothesis that synchronous hatching induced by maternal vibration in A. rotundus prevents sibling cannibalism. Mothers and their mature egg masses were allocated to three groups: synchronous hatching by maternal vibration (SHmv), synchronous hatching by artificial vibration (SHav), and asynchronous hatching (AH). We then investigated the influence of each hatching strategy on the occurrence of sibling cannibalism of eggs and early-instar nymphs in the laboratory. No difference in the proportion of eggs cannibalized was observed among the three groups. However, the proportion of nymphs cannibalized was higher in the AH group than in the SHmv group. The difference in the number of days to first molting within clutch was significantly higher in the AH group than in the SHmv group. Junior nymphs were sometimes eaten by senior nymphs. However, immediately after molting, senior nymphs were at a high risk of being eaten by junior nymphs. Our results indicate that synchronous hatching of A. rotundus is necessary to mitigate the risk of sibling cannibalism.},
}
@article {pmid29607027,
year = {2018},
author = {Best, R and Ruxton, GD and Gardner, A},
title = {Intragroup and intragenomic conflict over chemical defense against predators.},
journal = {Ecology and evolution},
volume = {8},
number = {6},
pages = {3322-3329},
doi = {10.1002/ece3.3926},
pmid = {29607027},
issn = {2045-7758},
abstract = {Insects are often chemically defended against predators. There is considerable evidence for a group-beneficial element to their defenses, and an associated potential for individuals to curtail their own investment in costly defense while benefitting from the investments of others, termed "automimicry." Although females in chemically defended taxa often lay their eggs in clusters, leading to siblings living in close proximity, current models of automimicry have neglected kin-selection effects, which may be expected to curb the evolution of such selfishness. Here, we develop a general theory of automimicry that explicitly incorporates kin selection. We investigate how female promiscuity modulates intragroup and intragenomic conflicts overinvestment into chemical defense, finding that individuals are favored to invest less than is optimal for their group, and that maternal-origin genes favor greater investment than do paternal-origin genes. We translate these conflicts into readily testable predictions concerning gene expression patterns and the phenotypic consequences of genomic perturbations, and discuss how our results may inform gene discovery in relation to economically important agricultural products.},
}
@article {pmid29606788,
year = {2018},
author = {Weiß, BM and Kücklich, M and Thomsen, R and Henkel, S and Jänig, S and Kulik, L and Birkemeyer, C and Widdig, A},
title = {Chemical composition of axillary odorants reflects social and individual attributes in rhesus macaques.},
journal = {Behavioral ecology and sociobiology},
volume = {72},
number = {4},
pages = {65},
doi = {10.1007/s00265-018-2479-5},
pmid = {29606788},
issn = {0340-5443},
support = {P40 OD012217/OD/NIH HHS/United States ; },
abstract = {Abstract: Scents play an important role in the life of most terrestrial mammals and may transmit valuable information about conspecifics. Olfaction was long considered of low importance in Old World monkeys due to their relative reduction of olfactory structures and low incidence of scent-marking behavior but has been increasingly recognized for mediating social relationships in recent years. Yet, studies investigating the composition of their chemical cues remain scarce. In the present study, we analyzed the potential information content of chemicals present on the skin of rhesus macaques (Macaca mulatta). We collected axillary secretions from 60 animals of the semifree-ranging population on Cayo Santiago (Puerto Rico, USA) with precleaned cotton swabs from which the secretions were subsequently extracted and analyzed by gas chromatography-mass spectrometry. Rhesus macaque axillary odorants varied in their overall similarity and composition. This variation was attributable to differences in sex, group membership, and kinship and further appeared to reflect age and rank in parts of our sample. The compounds most strongly associated with this variation primarily comprised larger molecular weight aldehydes and steroids. Such compounds are considered to be perceivable by the primate olfactory system through close-range interactions or through breakdown into smaller molecules by bacterial fermentation. Overall, our results provide additional evidence that odors of Old World monkeys reflect a wealth of potential information about their carrier, which provides the basis for chemical communication via body odors; however, its use by conspecifics needs to be confirmed in bioassays.

Significance statement: One prerequisite for olfactory communication is the presence of systematic variation in animal odors that is related to attributes such as age, sex, or kinship. The composition of odors has been examined in numerous mammals but, with the exception of humans, remains poorly understood in Old World monkeys and apes, taxonomic groups in which most species do not show scent-marking behavior. In the present study, we show that the composition of axillary secretions of an Old World monkey, the rhesus macaque, reflects sex, group membership, relatedness, and possibly also age and rank. This variation thus provides a basis for olfactory communication in Old World monkeys.},
}
@article {pmid29593107,
year = {2018},
author = {Shimoji, H and Kikuchi, T and Ohnishi, H and Kikuta, N and Tsuji, K},
title = {Social enforcement depending on the stage of colony growth in an ant.},
journal = {Proceedings. Biological sciences},
volume = {285},
number = {1875},
pages = {},
doi = {10.1098/rspb.2017.2548},
pmid = {29593107},
issn = {1471-2954},
abstract = {Altruism is a paradox in Darwinian evolution. Policing is an important mechanism of the evolution and maintenance of altruism. A recently developed dynamic game model incorporating colony demography and inclusive fitness predicts that, in hymenopteran social insects, policing behaviour enforcing reproductive altruism in group members depends strongly on the colony growth stage, with strong policing as the colony develops and a relaxation of policing during the reproductive phase. Here, we report clear evidence supporting this prediction. In the ant Diacamma sp., reproduction by workers was suppressed by worker policing when the colony was small, whereas in large, mature colonies worker policing was relaxed and worker-produced males emerged. Conditional expression of traits can provide strong empirical evidence for natural selection theory if the expression pattern is precisely predicted by the theory, and our results illustrate the importance of intracolony population dynamics in the evolution of social systems.},
}
@article {pmid29593076,
year = {2018},
author = {Brügger, RK and Kappeler-Schmalzriedt, T and Burkart, JM},
title = {Reverse audience effects on helping in cooperatively breeding marmoset monkeys.},
journal = {Biology letters},
volume = {14},
number = {3},
pages = {},
doi = {10.1098/rsbl.2018.0030},
pmid = {29593076},
issn = {1744-957X},
abstract = {Cooperatively breeding common marmosets show substantial variation in the amount of help they provide. Pay-to-stay and social prestige models of helping attribute this variation to audience effects, i.e. that individuals help more if group members can witness their interactions with immatures, whereas models of kin selection, group augmentation or those stressing the need to gain parenting experience do not predict any audience effects. We quantified the readiness of adult marmosets to share food in the presence or absence of other group members. Contrary to both predictions, we found a reverse audience effect on food-sharing behaviour: marmosets would systematically share more food with immatures when no audience was present. Thus, helping in common marmosets, at least in related family groups, does not support the pay-to-stay or the social prestige model, and helpers do not take advantage of the opportunity to engage in reputation management. Rather, the results appear to reflect a genuine concern for the immatures' well-being, which seems particularly strong when solely responsible for the immatures.},
}
@article {pmid29559642,
year = {2018},
author = {Towers, JR and Hallé, MJ and Symonds, HK and Sutton, GJ and Morton, AB and Spong, P and Borrowman, JP and Ford, JKB},
title = {Infanticide in a mammal-eating killer whale population.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {4366},
doi = {10.1038/s41598-018-22714-x},
pmid = {29559642},
issn = {2045-2322},
abstract = {Infanticide can be an extreme result of sexual conflict that drives selection in species in which it occurs. It is a rarely observed behaviour but some evidence for its occurrence in cetaceans exists in three species of dolphin. Here we describe observations of an adult male killer whale (Orcinus orca) and his post-reproductive mother killing a neonate belonging to an unrelated female from the same population in the North Pacific. This is the first account of infanticide reported in killer whales and the only case committed jointly by an adult male and his mother outside of humans. Consistent with findings in other social mammals, we suggest that infanticide is a sexually selected behaviour in killer whales that could provide subsequent mating opportunities for the infanticidal male and thereby provide inclusive fitness benefits for his mother.},
}
@article {pmid29558609,
year = {2017},
author = {Schultner, E and Oettler, J and Helanterä, H},
title = {The Role of Brood in Eusocial Hymenoptera.},
journal = {The Quarterly review of biology},
volume = {92},
number = {1},
pages = {39-78},
pmid = {29558609},
issn = {0033-5770},
mesh = {Animals ; *Behavior, Animal ; Female ; Hymenoptera/*physiology ; Male ; Population Dynamics ; *Social Behavior ; },
abstract = {Study of social traits in offspring traditionally reflects on interactions in simple family groups, with famous examples including parent-offspring conflict and sibling rivalry in birds and mammals. In contrast, studies of complex social groups such as the societies of ants, bees, and wasps focus mainly on adults and, in particular, on traits and interests of queens and workers. The social role of developing individuals in complex societies remains poorly understood. We attempt to fill this gap by illustrating that development in social Hymenoptera constitutes a crucial life stage with important consequences for the individual as well as the colony. We begin by describing the complex social regulatory network that modulates development in Hymenoptera societies. By highlighting the inclusive fitness interests of developing individuals, we show that they may differ from those of other colony members. We then demonstrate that offspring have evolved specialized traits that allow them to play a functional, cooperative role within colonies and give them the potential power to act toward increasing their inclusive fitness. We conclude by providing testable predictions for investigating the role of brood in colony interactions and giving a general outlook on what can be learned from studying offspring traits in hymenopteran societies.},
}
@article {pmid29543401,
year = {2018},
author = {Leedale, AE and Sharp, SP and Simeoni, M and Robinson, EJH and Hatchwell, BJ},
title = {Fine-scale genetic structure and helping decisions in a cooperatively breeding bird.},
journal = {Molecular ecology},
volume = {27},
number = {7},
pages = {1714-1726},
doi = {10.1111/mec.14553},
pmid = {29543401},
issn = {1365-294X},
abstract = {In animal societies, characteristic demographic and dispersal patterns may lead to genetic structuring of populations, generating the potential for kin selection to operate. However, even in genetically structured populations, social interactions may still require kin discrimination for cooperative behaviour to be directed towards relatives. Here, we use molecular genetics and long-term field data to investigate genetic structure in an adult population of long-tailed tits Aegithalos caudatus, a cooperative breeder in which helping occurs within extended kin networks, and relate this to patterns of helping with respect to kinship. Spatial autocorrelation analyses reveal fine-scale genetic structure within our population, such that related adults of either sex are spatially clustered following natal dispersal, with relatedness among nearby males higher than that among nearby females, as predicted by observations of male-biased philopatry. This kin structure creates opportunities for failed breeders to gain indirect fitness benefits via redirected helping, but crucially, most close neighbours of failed breeders are unrelated and help is directed towards relatives more often than expected by indiscriminate helping. These findings are consistent with the effective kin discrimination mechanism known to exist in long-tailed tits and support models identifying kin selection as the driver of cooperation.},
}
@article {pmid29525917,
year = {2018},
author = {Haemmerli, S and Thill, C and Amici, F and Cacchione, T},
title = {Domestic horses (Equus ferus caballus) fail to intuitively reason about object properties like solidity and weight.},
journal = {Animal cognition},
volume = {21},
number = {3},
pages = {441-446},
doi = {10.1007/s10071-018-1177-z},
pmid = {29525917},
issn = {1435-9456},
mesh = {Animals ; *Cognition ; Female ; Form Perception ; Horses/*psychology ; Learning ; Male ; Reward ; *Visual Perception ; },
abstract = {From early infancy, humans reason about the external world in terms of identifiable, solid, cohesive objects persisting in space and time. This is one of the most fundamental human skills, which may be part of our innate conception of object properties. Although object permanence has been extensively studied across a variety of taxa, little is known about how non-human animals reason about other object properties. In this study, we therefore tested how domestic horses (Equus ferus caballus) intuitively reason about object properties like solidity and height, to locate hidden food. Horses were allowed to look for a food reward behind two opaque screens, only one of which had either the proper height or inclination to hide food rewards. Our results suggest that horses could not intuitively reason about physical object properties, but rather learned to select the screen with the proper height or inclination from the second set of 5 trials.},
}
@article {pmid29515868,
year = {2018},
author = {Thomas, MG and Ji, T and Wu, J and He, Q and Tao, Y and Mace, R},
title = {Kinship underlies costly cooperation in Mosuo villages.},
journal = {Royal Society open science},
volume = {5},
number = {2},
pages = {171535},
doi = {10.1098/rsos.171535},
pmid = {29515868},
issn = {2054-5703},
abstract = {The relative importance of social evolution theories such as kin selection, direct reciprocity and need-based transfers in explaining real-world cooperation is the source of much debate. Previous field studies of cooperation in human communities have revealed variability in the extent to which each of these theories explains human sociality in different contexts. We conducted multivariate social network analyses predicting costly cooperation-labouring on another household's farm-in 128 082 dyads of Mosuo farming households in southwest China. Through information-theoretic model selection, we tested the roles played by genealogical relatedness, affinal relationships (including reproductive partners), reciprocity, relative need, wealth, household size, spatial proximity and gift-giving in an economic game. The best-fitting model included all factors, along with interactions between relatedness and (i) reciprocity, (ii) need, (iii) the presence of own children in another household and (iv) proximity. Our results show how a real-world form of cooperation was driven by kinship. Households tended to help kin in need (but not needy non-kin) and travel further to help spatially distant relatives. Households were more likely to establish reciprocal relationships with distant relatives and non-kin but closer kin cooperated regardless of reciprocity. These patterns of kin-driven cooperation show the importance of inclusive fitness in understanding human social behaviour.},
}
@article {pmid29515836,
year = {2018},
author = {Lehtonen, J and Schwanz, LE},
title = {Mate limitation and sex ratio evolution.},
journal = {Royal Society open science},
volume = {5},
number = {2},
pages = {171135},
doi = {10.1098/rsos.171135},
pmid = {29515836},
issn = {2054-5703},
abstract = {Sex ratio evolution has been one of the most successful areas of evolutionary theory. Pioneered by Düsing and Fisher under panmixia, and later extended by Hamilton to cover local mate competition (LMC), these models often assume, either implicitly or explicitly, that all females are fertilized. Here, we examine the effects of relaxing this assumption, under both panmictic and LMC models with diploid genetics. We revisit the question of the mathematical relationship between sex ratio and probability of fertilization, and use these results to model sex ratio evolution under risk of incomplete fertilization. We find that (i) under panmixia, mate limitation has no effect on the evolutionarily stable strategy (ESS) sex allocation; (ii) under LMC, mate limitation can make sex allocation less female-biased than under complete fertilization; (iii) contrary to what is occasionally stated, a significant fraction of daughters can remain unfertilized at the ESS in LMC with mate limitation; (iv) with a commonly used mating function, the fraction of unfertilized daughters can be quite large, and (v) with more realistic fertilization functions, the deviation becomes smaller. The models are presented in three equivalent forms: individual selection, kin selection and group selection. This serves as an example of the equivalence of the methods, while each approach has their own advantages. We discuss possible extensions of the model to haplodiploidy.},
}
@article {pmid29514963,
year = {2018},
author = {Schweinfurth, MK and Taborsky, M},
title = {Relatedness decreases and reciprocity increases cooperation in Norway rats.},
journal = {Proceedings. Biological sciences},
volume = {285},
number = {1874},
pages = {},
doi = {10.1098/rspb.2018.0035},
pmid = {29514963},
issn = {1471-2954},
abstract = {Kin selection and reciprocity are two mechanisms underlying the evolution of cooperation, but the relative importance of kinship and reciprocity for decisions to cooperate are yet unclear for most cases of cooperation. Here, we experimentally tested the relative importance of relatedness and received cooperation for decisions to help a conspecific in wild-type Norway rats (Rattus norvegicus). Test rats provided more food to non-kin than to siblings, and they generally donated more food to previously helpful social partners than to those that had refused help. The rats thus applied reciprocal cooperation rules irrespective of relatedness, highlighting the importance of reciprocal help for cooperative interactions among both related and unrelated conspecifics.},
}
@article {pmid29513655,
year = {2018},
author = {Kennedy, P and Higginson, AD and Radford, AN and Sumner, S},
title = {Altruism in a volatile world.},
journal = {Nature},
volume = {555},
number = {7696},
pages = {359-362},
doi = {10.1038/nature25965},
pmid = {29513655},
issn = {1476-4687},
support = {682253//European Research Council/International ; },
mesh = {*Altruism ; Animals ; *Biological Evolution ; Genetic Fitness ; Genotype ; Models, Biological ; Reproduction/genetics/physiology ; Selection, Genetic ; Stochastic Processes ; },
abstract = {The evolution of altruism-costly self-sacrifice in the service of others-has puzzled biologists since The Origin of Species. For half a century, attempts to understand altruism have developed around the concept that altruists may help relatives to have extra offspring in order to spread shared genes. This theory-known as inclusive fitness-is founded on a simple inequality termed Hamilton's rule. However, explanations of altruism have typically not considered the stochasticity of natural environments, which will not necessarily favour genotypes that produce the greatest average reproductive success. Moreover, empirical data across many taxa reveal associations between altruism and environmental stochasticity, a pattern not predicted by standard interpretations of Hamilton's rule. Here we derive Hamilton's rule with explicit stochasticity, leading to new predictions about the evolution of altruism. We show that altruists can increase the long-term success of their genotype by reducing the temporal variability in the number of offspring produced by their relatives. Consequently, costly altruism can evolve even if it has a net negative effect on the average reproductive success of related recipients. The selective pressure on volatility-suppressing altruism is proportional to the coefficient of variation in population fitness, and is therefore diminished by its own success. Our results formalize the hitherto elusive link between bet-hedging and altruism, and reveal missing fitness effects in the evolution of animal societies.},
}
@article {pmid29507206,
year = {2018},
author = {Noh, S and Geist, KS and Tian, X and Strassmann, JE and Queller, DC},
title = {Genetic signatures of microbial altruism and cheating in social amoebas in the wild.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {115},
number = {12},
pages = {3096-3101},
doi = {10.1073/pnas.1720324115},
pmid = {29507206},
issn = {1091-6490},
mesh = {Adaptation, Physiological ; Dictyostelium/*genetics/*physiology ; Evolution, Molecular ; Gene Expression Regulation ; Genetic Variation ; Genome, Protozoan ; Selection, Genetic ; },
abstract = {Many microbes engage in social interactions. Some of these have come to play an important role in the study of cooperation and conflict, largely because, unlike most animals, they can be genetically manipulated and experimentally evolved. However, whereas animal social behavior can be observed and assessed in natural environments, microbes usually cannot, so we know little about microbial social adaptations in nature. This has led to some difficult-to-resolve controversies about social adaptation even for well-studied traits such as bacterial quorum sensing, siderophore production, and biofilms. Here we use molecular signatures of population genetics and molecular evolution to address controversies over the existence of altruism and cheating in social amoebas. First, we find signatures of rapid adaptive molecular evolution that are consistent with social conflict being a significant force in nature. Second, we find population-genetic signatures of purifying selection to support the hypothesis that the cells that form the sterile stalk evolve primarily through altruistic kin selection rather than through selfish direct reproduction. Our results show how molecular signatures can provide insight into social adaptations that cannot be observed in their natural context, and they support the hypotheses that social amoebas in the wild are both altruists and cheaters.},
}
@article {pmid29494630,
year = {2018},
author = {Garay, J and Csiszár, V and Móri, TF and Szilágyi, A and Varga, Z and Számadó, S},
title = {Juvenile honest food solicitation and parental investment as a life history strategy: A kin demographic selection model.},
journal = {PloS one},
volume = {13},
number = {3},
pages = {e0193420},
doi = {10.1371/journal.pone.0193420},
pmid = {29494630},
issn = {1932-6203},
mesh = {Animals ; Feeding Behavior ; *Life History Traits ; Markov Chains ; *Models, Theoretical ; Phenotype ; Seasons ; },
abstract = {Parent-offspring communication remains an unresolved challenge for biologist. The difficulty of the challenge comes from the fact that it is a multifaceted problem with connections to life-history evolution, parent-offspring conflict, kin selection and signalling. Previous efforts mainly focused on modelling resource allocation at the expense of the dynamic interaction during a reproductive season. Here we present a two-stage model of begging where the first stage models the interaction between nestlings and parents within a nest and the second stage models the life-history trade-offs. We show in an asexual population that honest begging results in decreased variance of collected food between siblings, which leads to mean number of surviving offspring. Thus, honest begging can be seen as a special bet-hedging against informational uncertainty, which not just decreases the variance of fitness but also increases the arithmetic mean.},
}
@article {pmid29492037,
year = {2018},
author = {Wright, CM and Hyland, TD and Izzo, AS and McDermott, DR and Tibbetts, EA and Pruitt, JN},
title = {Polistes metricus queens exhibit personality variation and behavioral syndromes.},
journal = {Current zoology},
volume = {64},
number = {1},
pages = {45-52},
doi = {10.1093/cz/zox008},
pmid = {29492037},
issn = {1674-5507},
abstract = {Consistent differences in behavior between individuals, otherwise known as animal personalities, have become a staple in behavioral ecology due to their ability to explain a wide range of phenomena. Social organisms are especially serviceable to animal personality techniques because they can be used to explore behavioral variation at both the individual and group level. Despite the success of personality research in social organisms generally, and social Hymenoptera in particular, social wasps (Vespidae) have received little to no attention in the personality literature. In the present study, we test Polistes metricus (Vespidae; Polistinae) paper wasp queens for the presence of repeatable variation in, and correlations ("behavioral syndromes") between, several commonly used personality metrics: boldness, aggressiveness, exploration, and activity. Our results indicate that P. metricus queens exhibit personalities for all measured traits and correlations between different behavioral measures. Given that paper wasps have served as a model organism for a wide range of phenomena such as kin selection, dominance hierarchies, mate choice, facial recognition, social parasitism, and chemical recognition, we hope that our results will motivate researchers to explore whether, or to what degree, queen personality is important in their research programs.},
}
@article {pmid29491991,
year = {2017},
author = {Dale, R and Marshall-Pescini, S and Range, F},
title = {Do females use their sexual status to gain resource access? Investigating food-for-sex in wolves and dogs.},
journal = {Current zoology},
volume = {63},
number = {3},
pages = {323-330},
doi = {10.1093/cz/zow111},
pmid = {29491991},
issn = {1674-5507},
support = {311870//European Research Council/International ; },
abstract = {While food sharing among related individuals can be explained by kin selection, food sharing between unrelated individuals has been more of an evolutionary puzzle. The food-for-sex hypothesis provides an explanation for the occurrence of food sharing among nonkin. However, little is known about the socio-ecological factors that can promote such a commodity exchange. A species mating system is a factor potentially influencing food-for-sex patterns of behavior. Here, we compared wolves, which form pair-bonds, with dogs, which are typically promiscuous in free-ranging contexts, to investigate the effect of reproductive stages on the behavior around a food source in 2 different contexts. Furthermore, we considered the roles of both the males and the females in the potential food-for-sex exchange. Results indicate that in both species and for both sexes the breeding period promotes decreased aggression. Additionally, females were more persistent in their attempts to access the food and were able to monopolize the resource more when in heat as compared to outside the breeding period. Finally, in dogs, but not wolves, females spent more time in proximity to the male's bone and had a shorter latency to start eating it when in heat. Overall, this study demonstrates that the food-for-sex hypothesis plays a part in intersexual food sharing in canids, and highlights the role of females in the interaction. These effects were especially the case in dogs, suggesting a potential effect of mating system on food-for-sex responses.},
}
@article {pmid29449670,
year = {2018},
author = {Amici, F and Call, J and Watzek, J and Brosnan, S and Aureli, F},
title = {Social inhibition and behavioural flexibility when the context changes: a comparison across six primate species.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {3067},
doi = {10.1038/s41598-018-21496-6},
pmid = {29449670},
issn = {2045-2322},
abstract = {The ability to inhibit previously employed strategies and flexibly adjust behavioural responses to external conditions may be critical for individual survival. However, it is unclear which factors predict their distribution across species. Here, we investigated social inhibition and behavioural flexibility in six primate species (chimpanzees, bonobos, orangutans, gorillas, capuchin monkeys and spider monkeys) differing in terms of phylogenetic relatedness, foraging ecology and social organization. Depending on the social context, individuals could maximize their food intake by inhibiting the selection of a larger food reward in one condition (i.e. inhibition), but not in others, which required them to flexibly switching strategies across conditions (i.e. behavioural flexibility). Overall, our study revealed inter-specific differences in social inhibition and behavioural flexibility, which partially reflected differences in fission-fusion dynamics. In particular, orangutans and chimpanzees showed the highest level of inhibitory skills, while gorillas and capuchin monkeys showed the lowest one. In terms of behavioural flexibility, orangutans and spider monkeys were the best performers, while bonobos and capuchin monkeys were the worst ones. These results contribute to our understanding that inhibition and behavioural flexibility may be linked in more complex ways than usually thought, although both abilities play a crucial role in efficient problem solving.},
}
@article {pmid29438052,
year = {2018},
author = {Brahma, A and Mandal, S and Gadagkar, R},
title = {Current indirect fitness and future direct fitness are not incompatible.},
journal = {Biology letters},
volume = {14},
number = {2},
pages = {},
doi = {10.1098/rsbl.2017.0592},
pmid = {29438052},
issn = {1744-957X},
abstract = {In primitively eusocial insects, many individuals function as workers despite being capable of independent reproduction. Such altruistic behaviour is usually explained by the argument that workers gain indirect fitness by helping close genetic relatives. The focus on indirect fitness has left open the question of whether workers are also capable of getting direct fitness in the future in spite of working towards indirect fitness in the present. To investigate this question, we recorded behavioural profiles of all wasps on six naturally occurring nests of Ropalidia marginata, and then isolated all wasps in individual plastic boxes, giving them an opportunity to initiate nests and lay eggs. We found that 41% of the wasps successfully did so. Compared to those that failed to initiate nests, those that did were significantly younger, had significantly higher frequency of self-feeding behaviour on their parent nests but were not different in the levels of work performed in the parent nests. Thus ageing and poor feeding, rather than working for their colonies, constrain individuals for future independent reproduction. Hence, future direct fitness and present work towards gaining indirect fitness are not incompatible, making it easier for worker behaviour to be selected by kin selection or multilevel selection.},
}
@article {pmid29337077,
year = {2018},
author = {Pande, S and Velicer, GJ},
title = {Chimeric Synergy in Natural Social Groups of a Cooperative Microbe.},
journal = {Current biology : CB},
volume = {28},
number = {2},
pages = {262-267.e3},
doi = {10.1016/j.cub.2017.11.043},
pmid = {29337077},
issn = {1879-0445},
abstract = {Many cooperative species form internally diverse social groups in which individual fitness depends significantly on group-level productivity from cooperation [1-4]. For such species, selection is expected to often disfavor within-group diversity that reduces cooperative productivity [5, 6]. While diversity within social groups is known to enhance productivity in some animals [7-9], diversity within natural groups of social microbes is largely unexamined in this regard. Cells of the soil bacterium Myxococcus xanthus respond to starvation by constructing multicellular fruiting bodies within each of which a subpopulation of cells transforms into stress-resistant spores [10]. Fruiting bodies isolated from soil often harbor substantial endemic diversity [11] that is, nonetheless, lower than between-group diversity, which increases with distance from millimeter to global scales [12-14]. We show that M. xanthus clones isolated from the same fruiting body often collectively produce more viable spores in chimeric groups than expected from sporulation in genetically homogeneous groups. In contrast, chimerism among clones derived from different fruiting bodies tends to reduce group productivity, and it does so increasingly as a function of spatial distance between fruiting-body sample sites. For one fruiting body examined in detail, chimeric synergy-a positive quantitative effect of chimerism on group productivity-is distributed broadly across an interaction network rather than limited to a few interactions. We propose that these results strengthen the plausibility of the hypothesis that selection may operate not only within Myxococcus groups, but also between kin groups to disfavor within-group variation that reduces productivity while allowing some forms of diversity that generate chimeric synergy to persist.},
}
@article {pmid29295937,
year = {2018},
author = {Wang, C and Lu, X},
title = {Hamilton's inclusive fitness maintains heritable altruism polymorphism through rb = c.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {115},
number = {8},
pages = {1860-1864},
doi = {10.1073/pnas.1710215115},
pmid = {29295937},
issn = {1091-6490},
mesh = {*Altruism ; Animals ; Behavior, Animal ; Birds/*genetics ; Female ; *Genetic Fitness ; Genotype ; Male ; *Models, Genetic ; *Polymorphism, Genetic ; Social Behavior ; },
abstract = {How can altruism evolve or be maintained in a selfish world? Hamilton's rule shows that the former process will occur when rb > c-the benefits to the recipients of an altruistic act b, weighted by the relatedness between the social partners r, exceed the costs to the altruists c-drives altruistic genotypes spreading against nonaltruistic ones. From this rule, we infer that altruistic genotypes will persist in a population by forming a stable heritable polymorphism with nonaltruistic genotypes if rb = c makes inclusive fitness of the two morphs equal. We test this prediction using the data of 12 years of study on a cooperatively breeding bird, the Tibetan ground tit Pseudopodoces humilis, where helping is performed by males only and kin-directed. Individual variation in ever acting as a helper was heritable (h2 = 0.47), and the resultant altruism polymorphism remained stable as indicated by low-level annual fluctuation of the percentage of helpers among all adult males (24-28%). Helpers' indirect fitness gains from increased lifetime reproductive success of related breeders statistically fully compensated for their lifetime direct fitness losses, suggesting that rb = c holds. While our work provides a fundamental support for Hamilton's idea, it highlights the equivalent inclusive fitness returns to altruists and nonaltruists mediated by rb = c as a theoretically and realistically important mechanism to maintain social polymorphism.},
}
@article {pmid29289605,
year = {2018},
author = {Yamauchi, A and van Baalen, M and Sabelis, MW},
title = {Spatial patterns generated by simultaneous cooperation and exploitation favour the evolution of altruism.},
journal = {Journal of theoretical biology},
volume = {441},
number = {},
pages = {58-67},
doi = {10.1016/j.jtbi.2017.12.027},
pmid = {29289605},
issn = {1095-8541},
abstract = {In kin selection theory in the evolution of social behaviours, the relatedness between interacting individuals is influenced by the spatial structure of the population. It is generally considered that in the 'viscous' population competition among individuals tends to suppress the evolution of altruism. We consider that more complex interactions produce specific spatial patterns in the presence of competitive interaction, which could alter the process of kin selection in a given space. Here, we theoretically studied the joint evolution of altruism and resource exploitation in a spatially structured population. The simulations indicated that joint evolution can result in self-organisation of regularly arranged cluster structures, which creates a new 'level of selection', and significantly promotes the evolution of altruism through a promotion of kin selection. The analysis also suggested synergetic effects of the joint evolution of two traits, including an evolutionary suicide of the population.},
}
@article {pmid29244566,
year = {2018},
author = {Lehtonen, J},
title = {The Price Equation, Gradient Dynamics, and Continuous Trait Game Theory.},
journal = {The American naturalist},
volume = {191},
number = {1},
pages = {146-153},
doi = {10.1086/694891},
pmid = {29244566},
issn = {1537-5323},
mesh = {*Biological Evolution ; *Game Theory ; *Genetic Fitness ; Models, Genetic ; },
abstract = {A recent article convincingly nominated the Price equation as the fundamental theorem of evolution and used it as a foundation to derive several other theorems. A major section of evolutionary theory that was not addressed is that of game theory and gradient dynamics of continuous traits with frequency-dependent fitness. Deriving fundamental results in these fields under the unifying framework of the Price equation illuminates similarities and differences between approaches and allows a simple, unified view of game-theoretical and dynamic concepts. Using Taylor polynomials and the Price equation, I derive a dynamic measure of evolutionary change, a condition for singular points, the convergence stability criterion, and an alternative interpretation of evolutionary stability. Furthermore, by applying the Price equation to a multivariable Taylor polynomial, the direct fitness approach to kin selection emerges. Finally, I compare these results to the mean gradient equation of quantitative genetics and the canonical equation of adaptive dynamics.},
}
@article {pmid29244555,
year = {2018},
author = {Lion, S},
title = {Theoretical Approaches in Evolutionary Ecology: Environmental Feedback as a Unifying Perspective.},
journal = {The American naturalist},
volume = {191},
number = {1},
pages = {21-44},
doi = {10.1086/694865},
pmid = {29244555},
issn = {1537-5323},
mesh = {Adaptation, Biological ; *Biological Evolution ; Ecology/*methods ; Feedback ; *Game Theory ; Gene Frequency ; Genetic Fitness ; *Models, Genetic ; },
abstract = {Evolutionary biology and ecology have a strong theoretical underpinning, and this has fostered a variety of modeling approaches. A major challenge of this theoretical work has been to unravel the tangled feedback loop between ecology and evolution. This has prompted the development of two main classes of models. While quantitative genetics models jointly consider the ecological and evolutionary dynamics of a focal population, a separation of timescales between ecology and evolution is assumed by evolutionary game theory, adaptive dynamics, and inclusive fitness theory. As a result, theoretical evolutionary ecology tends to be divided among different schools of thought, with different toolboxes and motivations. My aim in this synthesis is to highlight the connections between these different approaches and clarify the current state of theory in evolutionary ecology. Central to this approach is to make explicit the dependence on environmental dynamics of the population and evolutionary dynamics, thereby materializing the eco-evolutionary feedback loop. This perspective sheds light on the interplay between environmental feedback and the timescales of ecological and evolutionary processes. I conclude by discussing some potential extensions and challenges to our current theoretical understanding of eco-evolutionary dynamics.},
}
@article {pmid29234885,
year = {2018},
author = {Gleichsner, AM and Reinhart, K and Minchella, DJ},
title = {The influence of related and unrelated co-infections on parasite dynamics and virulence.},
journal = {Oecologia},
volume = {186},
number = {2},
pages = {555-564},
doi = {10.1007/s00442-017-4035-9},
pmid = {29234885},
issn = {1432-1939},
abstract = {Many parasitic infections increase the morbidity and mortality of host populations. Interactions between co-infecting parasites can influence virulence, the damage done to a host. Previous studies investigating the impacts of parasite co-infection on hosts have been limited by their inability to control parasite dosage, use consistent virulence metrics, or verify co-infection status. This study used molecular tools, known infection dosage, and multiple assessments over time to test whether parasite relatedness can predict virulence in co-infections, as well as whether competitive interactions between different parasite strains within a host are predictable over time. In addition, we examined the impacts of other parasite traits, such as infectivity, as alternative predictors of virulence and competition outcomes. Hosts with single-strain (related) parasite infections were found to have lower virulence in terms of host and parasite reproduction, supporting kin selection predictions. However, these infections also resulted in higher host mortality. We argue that mortality should not be used as a measurement of virulence in parasite systems that castrate hosts. Hosts were more susceptible to mixed strain (unrelated) parasite infections, indicating that co-infections may make resistance more costly to hosts. Co-infections were dynamic, with changes in parasite dominance over the course of the infection. The more infective parasite strain appeared to suppress the less infective strain, ultimately increasing host longevity. Our findings suggest that unrelated, or more diverse, parasite infections are associated with higher virulence, but that studies must consider their methodology and possible alternative explanations beyond kin selection to understand virulence outcomes.},
}
@article {pmid29206171,
year = {2017},
author = {Levin, SR and West, SA},
title = {Kin Selection in the RNA World.},
journal = {Life (Basel, Switzerland)},
volume = {7},
number = {4},
pages = {},
doi = {10.3390/life7040053},
pmid = {29206171},
issn = {2075-1729},
abstract = {Various steps in the RNA world required cooperation. Why did life's first inhabitants, from polymerases to synthetases, cooperate? We develop kin selection models of the RNA world to answer these questions. We develop a very simple model of RNA cooperation and then elaborate it to model three relevant issues in RNA biology: (1) whether cooperative RNAs receive the benefits of cooperation; (2) the scale of competition in RNA populations; and (3) explicit replicator diffusion and survival. We show: (1) that RNAs are likely to express partial cooperation; (2) that RNAs will need mechanisms for overcoming local competition; and (3) in a specific example of RNA cooperation, persistence after replication and offspring diffusion allow for cooperation to overcome competition. More generally, we show how kin selection can unify previously disparate answers to the question of RNA world cooperation.},
}
@article {pmid29195838,
year = {2018},
author = {Sanches, VH and Kuraoka, DVH and Almeida, PR and Goldman, C},
title = {A phenomenological analysis of eco-evolutionary coupling under dilution.},
journal = {Journal of theoretical biology},
volume = {438},
number = {},
pages = {156-164},
doi = {10.1016/j.jtbi.2017.11.019},
pmid = {29195838},
issn = {1095-8541},
mesh = {*Biological Evolution ; *Ecosystem ; *Models, Biological ; Numerical Analysis, Computer-Assisted ; Saccharomyces cerevisiae/metabolism ; Time Factors ; },
abstract = {Evolutionary dynamics experienced by mixed microbial populations of cooperators and cheaters has been examined in experiments in the literature using a protocol of periodic dilution to investigate the properties of resilience and adaptability to environmental changes. Data depicted on an appropriate phase diagram indicate, among other features, a stable equilibrium point at which cooperators and cheaters coexist (Sanchez and Gore, 2013). We present here a phenomenological analysis of these data focusing on an eco-evolutionary-game perspective. To that end, we work on an extension of the model proposed in Tao and Cressman (2007). It's original version takes into account changes of the total population density while the individuals experience a pairwise Prisoners Dilemma game. The extension devised here contains a dilution parameter to conform with the experimental procedure, in addition to a term accounting for Allee effects. In contrast to other descriptions proposed in similar contexts, however, the model here does not account for assortative encounters, group or kin selection. Nonetheless, it describes surprisingly well both qualitatively and quantitatively the features of the observed phase diagram. We discuss these results in terms of the behavior of an effective payoff matrix defined accordingly.},
}
@article {pmid29179582,
year = {2017},
author = {Zhang, J},
title = {Is Support of Censoring Controversial Media Content for the Good of Others? Sexual Strategies and Support of Censoring Pro-Alcohol Advertising.},
journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior},
volume = {15},
number = {4},
pages = {1474704917742808},
doi = {10.1177/1474704917742808},
pmid = {29179582},
issn = {1474-7049},
mesh = {Adolescent ; Adult ; *Advertising as Topic ; *Alcohol Drinking ; *Alcoholic Beverages ; Female ; Humans ; Male ; *Sexual Behavior ; United States ; Young Adult ; },
abstract = {At least in the United States, there are widespread concerns with advertising that encourages alcohol consumption, and previous research explains those concerns as aiming to protect others from the harm of excessive alcohol use.1 Drawing on sexual strategies theory, we hypothesized that support of censoring pro-alcohol advertising is ultimately self-benefiting regardless of its altruistic effect at a proximate level. Excessive drinking positively correlates with having casual sex, and casual sex threatens monogamy, one of the major means with which people adopting a long-term sexual strategy increase their inclusive fitness. Then, one way for long-term strategists to protect monogamy, and thus their reproductive interest is to support censoring pro-alcohol advertising, thereby preventing others from becoming excessive drinkers (and consequently having casual sex) under media influence. Supporting this hypothesis, three studies consistently showed that restricted sociosexuality positively correlated with support of censoring pro-alcohol advertising before and after various value-, ideological-, and moral-foundation variables were controlled for. Also as predicted, Study 3 revealed a significant indirect effect of sociosexuality on censorship support through perceived media influence on others but not through perceived media influence on self. These findings further supported a self-interest analysis of issue opinions, extended third-person-effect research on support of censoring pro-alcohol advertising, and suggested a novel approach to analyzing media censorship support.},
}
@article {pmid29166167,
year = {2017},
author = {Riehl, C},
title = {Kinship and Incest Avoidance Drive Patterns of Reproductive Skew in Cooperatively Breeding Birds.},
journal = {The American naturalist},
volume = {190},
number = {6},
pages = {774-785},
doi = {10.1086/694411},
pmid = {29166167},
issn = {1537-5323},
mesh = {Animals ; Birds/*genetics/*physiology ; Female ; *Inbreeding ; Male ; Reproduction/physiology ; *Social Behavior ; Species Specificity ; },
abstract = {Social animals vary in how reproduction is divided among group members, ranging from monopolization by a dominant pair (high skew) to equal sharing by cobreeders (low skew). Despite many theoretical models, the ecological and life-history factors that generate this variation are still debated. Here I analyze data from 83 species of cooperatively breeding birds, finding that kinship within the breeding group is a powerful predictor of reproductive sharing across species. Societies composed of nuclear families have significantly higher skew than those that contain unrelated members, a pattern that holds for both multimale and multifemale groups. Within-species studies confirm this, showing that unrelated subordinates of both sexes are more likely to breed than related subordinates are. Crucially, subordinates in cooperative groups are more likely to breed if they are unrelated to the opposite-sex dominant, whereas relatedness to the same-sex dominant has no effect. This suggests that incest avoidance, rather than suppression by dominant breeders, may be an important proximate mechanism limiting reproduction by subordinates. Overall, these results support the ultimate evolutionary logic behind concessions models of skew-namely, that related subordinates gain indirect fitness benefits from helping at the nests of kin, so a lower direct reproductive share is required for selection to favor helping over dispersal-but not the proximate mechanism of dominant control assumed by these models.},
}
@article {pmid29142115,
year = {2017},
author = {Lymbery, SJ and Simmons, LW},
title = {Males harm females less when competing with familiar relatives.},
journal = {Proceedings. Biological sciences},
volume = {284},
number = {1867},
pages = {},
doi = {10.1098/rspb.2017.1984},
pmid = {29142115},
issn = {1471-2954},
mesh = {*Aggression ; Animals ; Coleoptera/*physiology ; Female ; Male ; *Sexual Behavior, Animal ; },
abstract = {Sexual conflict occurs when reproductive partners have different fitness optima, and can lead to the evolution of traits in one sex that inflict fitness costs on the opposite sex. Recently, it has been proposed that antagonism by males towards females should be reduced when they compete with relatives, because reducing the future productivity of a female would result in an indirect fitness cost for a harmful male. We tested this prediction in the seed beetle Callosobruchus maculatus, the males of which harm females with genital spines and pre-copulatory harassment. We compared lifespan, lifetime egg production and lifetime offspring production among females housed with groups of males that varied in their familiarity and relatedness. Females produced significantly more eggs and offspring when grouped with males who were both related and familiar to each other. There was no effect of male relatedness or familiarity on female lifespan. Our results suggest that males plastically adjust their harmfulness towards females in response to changes in inclusive fitness payoffs, and that in this species both genetic relatedness and social familiarity mediate this effect.},
}
@article {pmid29134064,
year = {2017},
author = {Bertolaso, M and Dieli, AM},
title = {Cancer and intercellular cooperation.},
journal = {Royal Society open science},
volume = {4},
number = {10},
pages = {170470},
doi = {10.1098/rsos.170470},
pmid = {29134064},
issn = {2054-5703},
abstract = {The major transitions approach in evolutionary biology has shown that the intercellular cooperation that characterizes multicellular organisms would never have emerged without some kind of multilevel selection. Relying on this view, the Evolutionary Somatic view of cancer considers cancer as a breakdown of intercellular cooperation and as a loss of the balance between selection processes that take place at different levels of organization (particularly single cell and individual organism). This seems an elegant unifying framework for healthy organism, carcinogenesis, tumour proliferation, metastasis and other phenomena such as ageing. However, the gene-centric version of Darwinian evolution, which is often adopted in cancer research, runs into empirical problems: proto-tumoural and tumoural features in precancerous cells that would undergo 'natural selection' have proved hard to demonstrate; cells are radically context-dependent, and some stages of cancer are poorly related to genetic change. Recent perspectives propose that breakdown of intercellular cooperation could depend on 'fields' and other higher-level phenomena, and could be even mutations independent. Indeed, the field would be the context, allowing (or preventing) genetic mutations to undergo an intra-organism process analogous to natural selection. The complexities surrounding somatic evolution call for integration between multiple incomplete frameworks for interpreting intercellular cooperation and its pathologies.},
}
@article {pmid29118238,
year = {2017},
author = {Smith, D},
title = {Correction to 'O brother, where art thou? Investment in siblings for inclusive fitness benefits, not father absence, predicts earlier age at menarche'.},
journal = {Biology letters},
volume = {13},
number = {11},
pages = {},
doi = {10.1098/rsbl.2017.0650},
pmid = {29118238},
issn = {1744-957X},
}
@article {pmid29109471,
year = {2017},
author = {Gardner, A and Úbeda, F},
title = {The meaning of intragenomic conflict.},
journal = {Nature ecology & evolution},
volume = {1},
number = {12},
pages = {1807-1815},
doi = {10.1038/s41559-017-0354-9},
pmid = {29109471},
issn = {2397-334X},
mesh = {*Biological Evolution ; Genetic Fitness ; *Genome ; Models, Genetic ; *Selection, Genetic ; },
abstract = {Recent years have seen an explosion of interest in genes that function for their own good and to the detriment of other genes that reside in the same genome. Such intragenomic conflicts are increasingly recognized to underpin maladaptation and disease. However, progress has been impeded by a lack of clear understanding regarding what intragenomic conflict actually means, and an associated obscurity concerning its fundamental drivers. Here we develop a general theory of intragenomic conflict in which genes are viewed as inclusive-fitness-maximizing agents that come into conflict when their inclusive-fitness interests disagree. This yields a classification of all intragenomic conflicts into three categories according to whether genes disagree about where they have come from, where they are going, or where they currently are. We illustrate each of these three basic categories, survey and classify all known forms of intragenomic conflict, and discuss the implications for organismal maladaptation and human disease.},
}
@article {pmid29080969,
year = {2018},
author = {Tornero, E and Sánchez-Romera, JF and Morosoli, JJ and Vázquez, A and Gómez, Á and Ordoñana, JR},
title = {Altruistic Behavior among Twins : Willingness to Fight and Self-Sacrifice for Their Closest Relatives.},
journal = {Human nature (Hawthorne, N.Y.)},
volume = {29},
number = {1},
pages = {1-12},
doi = {10.1007/s12110-017-9304-0},
pmid = {29080969},
issn = {1936-4776},
support = {19479/PI/14//Fundación Séneca/ ; PSI2014-56680-R//Ministerio de Economía y Competitividad/ ; PSI2015-67754-P//Ministerio de Economía y Competitividad/ ; },
mesh = {Adult ; Aggression/*psychology ; *Altruism ; Female ; Humans ; Male ; *Sibling Relations ; Twins, Dizygotic/*psychology ; Twins, Monozygotic/*psychology ; },
abstract = {According to kin selection theory, indirect reproductive advantages may induce individuals to care for others with whom they share genes by common descent, and the amount of care, including self-sacrifice, will increase with the proportion of genes shared. Twins represent a natural situation in which this hypothesis can be tested. Twin pairs experience the same early environment because they were born and raised at the same time and in the same family but their genetic relatedness differs depending on zygosity. We compared the degree of willingness to fight and sacrifice for the co-twin among monozygotic (MZ) and dizygotic (DZ) pairs in a sample of 1443 same-sex and opposite-sex twins. We also analyzed the effect of the subject's gender and that of the co-twin on those altruistic behaviors. Results partly supported the postulated explanation. MZ twins (who share nearly their entire genome) were significantly more likely than DZ twins (who on average share half of their segregating genes) to self-sacrifice for their co-twins, but zygosity did not affect willingness to fight for him/her. The genders of the subject and of the co-twin, not genetic relatedness, were the best predictors of aggressive altruistic intentions.},
}
@article {pmid29073100,
year = {2017},
author = {Bebbington, K and Kingma, SA and Fairfield, EA and Dugdale, HL and Komdeur, J and Spurgin, LG and Richardson, DS},
title = {Kinship and familiarity mitigate costs of social conflict between Seychelles warbler neighbors.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {114},
number = {43},
pages = {E9036-E9045},
doi = {10.1073/pnas.1704350114},
pmid = {29073100},
issn = {1091-6490},
mesh = {*Aggression ; Animal Distribution ; Animals ; Ecosystem ; Female ; Genotype ; Male ; Passeriformes/*genetics/physiology ; Recognition (Psychology) ; Seychelles ; *Territoriality ; },
abstract = {Because virtually all organisms compete with others in their social environment, mechanisms that reduce conflict between interacting individuals are crucial for the evolution of stable families, groups, and societies. Here, we tested whether costs of social conflict over territorial space between Seychelles warblers (Acrocephalus sechellensis) are mitigated by kin-selected (genetic relatedness) or mutualistic (social familiarity) mechanisms. By measuring longitudinal changes in individuals' body mass and telomere length, we demonstrated that the fitness costs of territoriality are driven by a complex interplay between relatedness, familiarity, local density, and sex. Physical fights were less common at territory boundaries shared between related or familiar males. In line with this, male territory owners gained mass when living next to related or familiar males and also showed less telomere attrition when living next to male kin. Importantly, these relationships were strongest in high-density areas of the population. Males also had more rapid telomere attrition when living next to unfamiliar male neighbors, but mainly when relatedness to those neighbors was also low. In contrast, neither kinship nor familiarity was linked to body mass or telomere loss in female territory owners. Our results indicate that resolving conflict over territorial space through kin-selected or mutualistic pathways can reduce both immediate energetic costs and permanent somatic damage, thus providing an important mechanism to explain fine-scale population structure and cooperation between different social units across a broad range of taxa.},
}
@article {pmid29061969,
year = {2017},
author = {Kingma, SA},
title = {Direct benefits explain interspecific variation in helping behaviour among cooperatively breeding birds.},
journal = {Nature communications},
volume = {8},
number = {1},
pages = {1094},
doi = {10.1038/s41467-017-01299-5},
pmid = {29061969},
issn = {2041-1723},
mesh = {Animals ; Behavior, Animal/*physiology ; Birds/*physiology ; Breeding ; Cooperative Behavior ; Helping Behavior ; Nesting Behavior/physiology ; Species Specificity ; },
abstract = {Kin selection theory provides one important explanation for seemingly altruistic helping behaviour by non-breeding subordinates in cooperative breeding animals. However, it cannot explain why helpers in many species provide energetically costly care to unrelated offspring. Here, I use comparative analyses to show that direct fitness benefits of helping others, associated with future opportunities to breed in the resident territory, are responsible for the widespread variation in helping effort (offspring food provisioning) and kin discrimination across cooperatively breeding birds. In species where prospects of territory inheritance are larger, subordinates provide more help, and, unlike subordinates that cannot inherit a territory, do not preferentially direct care towards related offspring. Thus, while kin selection can underlie helping behaviour in some species, direct benefits are much more important than currently recognised and explain why unrelated individuals provide substantial help in many bird species.},
}
@article {pmid29055381,
year = {2017},
author = {Riordan, DV},
title = {Mimetic Theory and the evolutionary paradox of schizophrenia: The archetypal scapegoat hypothesis.},
journal = {Medical hypotheses},
volume = {108},
number = {},
pages = {101-107},
doi = {10.1016/j.mehy.2017.08.010},
pmid = {29055381},
issn = {1532-2777},
mesh = {*Altruism ; *Biological Evolution ; Cultural Characteristics ; Environment ; Humans ; *Interpersonal Relations ; Language ; Models, Biological ; Models, Psychological ; Religion ; Risk ; Schizophrenia/*physiopathology ; *Social Behavior ; Social Stigma ; Violence ; },
abstract = {Schizophrenia poses an evolutionary paradox, being genetically mediated yet associated with reduced fecundity. Numerous hypotheses have attempted to address this, but few describe how the schizophrenic phenotype itself might constitute an evolutionary adaptation. This paper draws on René Girard's theory on human origins, which claims that humans evolved a tendency to mimic both the desires and the behaviours of each other (mimetic theory). This would have promoted social cohesion and co-operation, but at the cost of intra-group rivalry and conflict. The mimetic dynamic would have escalated such conflicts into reciprocal internecine violence, threatening the survival of the entire group. Girard theorised that the "scapegoat mechanism" emerged, by which means such violence was curtailed by the unanimity of "all against one", thus allowing the mimetic impulse to safely evolve further, making language and complex social behaviours possible. Whereas scapegoating may have emerged in the entire population, and any member of a community could be scapegoated if necessary, this paper proposes that the scapegoat mechanism would have worked better in groups containing members who exhibited traits, recognised by all others, which singled them out as victims. Schizophrenia may be a functional adaptation, similar in evolutionary terms to altruism, in that it may have increased inclusive fitness, by providing scapegoat victims, the choice of whom was likely to be agreed upon unanimously, even during internecine conflict, thus restoring order and protecting the group from self-destruction. This evolutionary hypothesis, uses Girardian anthropology to combine the concept of the schizophrenic as religious shaman with that of the schizophrenic as scapegoat. It may help to reconcile divergent philosophical concepts of mental illness, and also help us to better understand, and thus counter, social exclusion and stigmatisation.},
}
@article {pmid29046373,
year = {2017},
author = {Smith, D},
title = {O brother, where art thou? Investment in siblings for inclusive fitness benefits, not father absence, predicts earlier age at menarche.},
journal = {Biology letters},
volume = {13},
number = {10},
pages = {},
doi = {10.1098/rsbl.2017.0464},
pmid = {29046373},
issn = {1744-957X},
support = {MC_PC_15018//Medical Research Council/United Kingdom ; },
mesh = {Adolescent ; Age Factors ; Child ; England ; *Fathers ; Female ; Humans ; Longitudinal Studies ; Male ; Menarche/*physiology ; *Paternal Deprivation ; *Siblings ; },
abstract = {Numerous studies have indicated that father absence is associated with earlier age at menarche, with many evolutionary theories assuming that father absence is a causal factor that accelerates reproductive development. However, an alternative interpretation suggests that offspring may reproduce earlier in the presence of half- or step-siblings as the indirect fitness benefits to investing in them are lower, relative to delaying reproduction and investing in full siblings. From this perspective, father absence may perform no causal role in facilitating the onset of menarche. Using data from the Avon Longitudinal Study of Parents and Children, I find that individuals with only half- or step-siblings reach reproductive age earlier than those with only full siblings, with no independent effect of father absence. These results suggest that inclusive fitness benefits to investing in siblings, rather than father absence, may predict variation in age at menarche. These results provide a greater understanding of the adaptive mechanisms involved in reproductive decision-making, as well as potential implications for human life-history evolution and cooperative breeding more broadly.},
}
@article {pmid29021183,
year = {2017},
author = {Levin, SR and West, SA},
title = {The evolution of cooperation in simple molecular replicators.},
journal = {Proceedings. Biological sciences},
volume = {284},
number = {1864},
pages = {},
doi = {10.1098/rspb.2017.1967},
pmid = {29021183},
issn = {1471-2954},
mesh = {Animals ; Bacteria/genetics ; Biological Evolution ; *Evolution, Molecular ; *Genome ; *Life History Traits ; Models, Genetic ; Social Behavior ; },
abstract = {In order for the first genomes to evolve, independent replicators had to act cooperatively, with some reducing their own replication rate to help copy others. It has been argued that limited diffusion explains this early cooperation. However, social evolution models have shown that limited diffusion on its own often does not favour cooperation. Here we model early replicators using social evolution tools. We show that: (i) replicators can be considered to be cooperating as a result of kin selection; (ii) limited diffusion on its own does not favour cooperation; and (iii) the addition of overlapping generations, probably a general trait of molecular replicators, promotes cooperation. These results suggest key life-history features in the evolution of the genome and that the same factors can favour cooperation across the entire tree of life.},
}
@article {pmid28977660,
year = {2017},
author = {Gong, X and Zhang, F and Fung, HH},
title = {Are Older Adults More Willing to Donate? The Roles of Donation Form and Social Relationship.},
journal = {The journals of gerontology. Series B, Psychological sciences and social sciences},
volume = {},
number = {},
pages = {},
doi = {10.1093/geronb/gbx099},
pmid = {28977660},
issn = {1758-5368},
abstract = {Objectives: Whether older adults are more prosocial than younger adults has been under debate. In the current study, we investigated how age differences in prosocial behaviors varied across different contextual factors, that is, donation form, kinship, and social distance.

Methods: To achieve this purpose, 89 younger and 66 older adults took part in a hypothetical donation task in which they were asked to donate money and time to relatives and nonrelatives at various social distances.

Results: The results showed that, compared to younger adults, (a) older adults donated less to nonrelatives (regardless of the donation form), but donated a similar amount (in money) or even donated more (in time) to relatives; (b) older adults displayed higher levels of kin selection (favoring relatives over nonrelatives) in both monetary and time donations; and (c) older adults showed higher levels of social discounting (favoring socially close over distant others) in monetary but not time donation.

RESULTS: Egg production with two types of eggs, namely reproductive and trophic eggs, by physogastric workers was found. The reproductive egg was confirmed to be haploid and male-destined, suggesting that the workers produced males via arrhenotokous parthenogenesis as no spermatheca was discovered. Detailed observations suggested that larvae were mainly fed with trophic eggs. Along with consumption of trophic eggs by queens and other castes as part of their diet, the vital role of physogastric workers as "trophic specialist" is confirmed.

CONCLUSION: We propose that adaptive advantages derived from worker reproduction for A. gracilipes may include 1) trophic eggs provisioned by physogastric workers likely assist colonies of A. gracilipes in overcoming unfavorable conditions such as paucity of food during critical founding stage; 2) worker-produced males are fertile and thus might offer an inclusive fitness advantage for the doomed orphaned colony.},
}
@article {pmid28487486,
year = {2017},
author = {Dugatkin, LA},
title = {Long reach of inclusive fitness.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {114},
number = {20},
pages = {5067-5068},
doi = {10.1073/pnas.1705324114},
pmid = {28487486},
issn = {1091-6490},
mesh = {Biological Evolution ; *Genetic Fitness ; Models, Genetic ; *Selection, Genetic ; },
}
@article {pmid28469021,
year = {2017},
author = {Cornioley, T and Jenouvrier, S and Börger, L and Weimerskirch, H and Ozgul, A},
title = {Fathers matter: male body mass affects life-history traits in a size-dimorphic seabird.},
journal = {Proceedings. Biological sciences},
volume = {284},
number = {1854},
pages = {},
doi = {10.1098/rspb.2017.0397},
pmid = {28469021},
issn = {1471-2954},
mesh = {Animals ; Birds/*physiology ; *Body Size ; Climate Change ; Fathers ; Female ; Male ; Population Dynamics ; Reproduction ; *Sex Characteristics ; },
abstract = {One of the predicted consequences of climate change is a shift in body mass distributions within animal populations. Yet body mass, an important component of the physiological state of an organism, can affect key life-history traits and consequently population dynamics. Over the past decades, the wandering albatross-a pelagic seabird providing bi-parental care with marked sexual size dimorphism-has exhibited an increase in average body mass and breeding success in parallel with experiencing increasing wind speeds. To assess the impact of these changes, we examined how body mass affects five key life-history traits at the individual level: adult survival, breeding probability, breeding success, chick mass and juvenile survival. We found that male mass impacted all traits examined except breeding probability, whereas female mass affected none. Adult male survival increased with increasing mass. Increasing adult male mass increased breeding success and mass of sons but not of daughters. Juvenile male survival increased with their chick mass. These results suggest that a higher investment in sons by fathers can increase their inclusive fitness, which is not the case for daughters. Our study highlights sex-specific differences in the effect of body mass on the life history of a monogamous species with bi-parental care.},
}
@article {pmid28469015,
year = {2017},
author = {Vitikainen, EIK and Marshall, HH and Thompson, FJ and Sanderson, JL and Bell, MBV and Gilchrist, JS and Hodge, SJ and Nichols, HJ and Cant, MA},
title = {Biased escorts: offspring sex, not relatedness explains alloparental care patterns in a cooperative breeder.},
journal = {Proceedings. Biological sciences},
volume = {284},
number = {1854},
pages = {},
doi = {10.1098/rspb.2016.2384},
pmid = {28469015},
issn = {1471-2954},
mesh = {Animals ; *Cooperative Behavior ; Female ; *Helping Behavior ; Herpestidae/*physiology ; Male ; },
abstract = {Kin selection theory predicts that animals should direct costly care where inclusive fitness gains are highest. Individuals may achieve this by directing care at closer relatives, yet evidence for such discrimination in vertebrates is equivocal. We investigated patterns of cooperative care in banded mongooses, where communal litters are raised by adult 'escorts' who form exclusive caring relationships with individual pups. We found no evidence that escorts and pups assort by parentage or relatedness. However, the time males spent escorting increased with increasing relatedness to the other group members, and to the pup they had paired with. Thus, we found no effect of relatedness in partner choice, but (in males) increasing helping effort with relatedness once partner choices had been made. Unexpectedly, the results showed clear assortment by sex, with female carers being more likely to tend to female pups, and male carers to male pups. This sex-specific assortment in helping behaviour has potential lifelong impacts on individual development and may impact the future size and composition of natal groups and dispersing cohorts. Where relatedness between helpers and recipients is already high, individuals may be better off choosing partners using other predictors of the costs and benefits of cooperation, without the need for possibly costly within-group kin discrimination.},
}
@article {pmid30283638,
year = {2017},
author = {O'Brien, EK and Wolf, JB},
title = {The coadaptation theory for genomic imprinting.},
journal = {Evolution letters},
volume = {1},
number = {1},
pages = {49-59},
doi = {10.1002/evl3.5},
pmid = {30283638},
issn = {2056-3744},
abstract = {Imprinted genes are peculiar in that expression of the two copies differs depending on whether the copy was maternally or paternally inherited. The discovery of this striking pattern of gene expression inspired myriad evolutionary theories, the most successful of which identify scenarios that create an asymmetry between the maternally and paternally inherited gene copies that favors silencing of one of the copies. Most notably, imprinting can evolve when gene dosage affects kin interactions (typically involving conflict) or when silencing enhances coadaptation by coordinating traits expressed by interacting kin. Although we have a well-established theory for the former process (the "Kinship Theory"), the coadaptation process has only been explored for the specific case of interactions between mothers and offspring. Here, we fill this critical gap in our understanding by developing a general "Coadaptation Theory" that explains how imprinting can evolve to coordinate interactions between all types of relatives. Using a simple model in which fitness of an individual is determined by an interaction between its own phenotype (and hence genotype) and that of its social partner(s), we find that when the relatedness of interactants differs through their maternally versus paternally inherited gene copies, then selection favors expression of the allele through which relatedness is higher. The predictions of this Coadaptation Theory potentially apply whenever a gene underlies traits that mediate the outcome of conspecific interactions, regardless of their mechanism or the type of organism, and therefore provide a potential explanation for enigmatic patterns of imprinting, including those underlying adult traits. By providing simple testable predictions that often directly contrast with those derived from alternative theories, our model should play an important role in consolidating our understanding of the evolution of imprinting across genes and species, which will ultimately provide crucial insights into imprinted gene function and dysfunction.},
}
@article {pmid28439031,
year = {2017},
author = {Thompson, FJ and Cant, MA and Marshall, HH and Vitikainen, EIK and Sanderson, JL and Nichols, HJ and Gilchrist, JS and Bell, MBV and Young, AJ and Hodge, SJ and Johnstone, RA},
title = {Explaining negative kin discrimination in a cooperative mammal society.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {114},
number = {20},
pages = {5207-5212},
doi = {10.1073/pnas.1612235114},
pmid = {28439031},
issn = {1091-6490},
support = {BB/H022716/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; },
mesh = {Aggression/psychology ; Animals ; Behavior, Animal ; *Conflict (Psychology) ; *Cooperative Behavior ; Dominance-Subordination ; Family/*psychology ; Female ; Game Theory ; Herpestidae/*psychology ; Inbreeding ; Male ; Reproduction ; Social Behavior ; },
abstract = {Kin selection theory predicts that, where kin discrimination is possible, animals should typically act more favorably toward closer genetic relatives and direct aggression toward less closely related individuals. Contrary to this prediction, we present data from an 18-y study of wild banded mongooses, Mungos mungo, showing that females that are more closely related to dominant individuals are specifically targeted for forcible eviction from the group, often suffering severe injury, and sometimes death, as a result. This pattern cannot be explained by inbreeding avoidance or as a response to more intense local competition among kin. Instead, we use game theory to show that such negative kin discrimination can be explained by selection for unrelated targets to invest more effort in resisting eviction. Consistent with our model, negative kin discrimination is restricted to eviction attempts of older females capable of resistance; dominants exhibit no kin discrimination when attempting to evict younger females, nor do they discriminate between more closely or less closely related young when carrying out infanticidal attacks on vulnerable infants who cannot defend themselves. We suggest that in contexts where recipients of selfish acts are capable of resistance, the usual prediction of positive kin discrimination can be reversed. Kin selection theory, as an explanation for social behavior, can benefit from much greater exploration of sequential social interactions.},
}
@article {pmid28435860,
year = {2017},
author = {Wang, Z and Jusup, M and Wang, RW and Shi, L and Iwasa, Y and Moreno, Y and Kurths, J},
title = {Onymity promotes cooperation in social dilemma experiments.},
journal = {Science advances},
volume = {3},
number = {3},
pages = {e1601444},
doi = {10.1126/sciadv.1601444},
pmid = {28435860},
issn = {2375-2548},
abstract = {One of the most elusive scientific challenges for over 150 years has been to explain why cooperation survives despite being a seemingly inferior strategy from an evolutionary point of view. Over the years, various theoretical scenarios aimed at solving the evolutionary puzzle of cooperation have been proposed, eventually identifying several cooperation-promoting mechanisms: kin selection, direct reciprocity, indirect reciprocity, network reciprocity, and group selection. We report the results of repeated Prisoner's Dilemma experiments with anonymous and onymous pairwise interactions among individuals. We find that onymity significantly increases the frequency of cooperation and the median payoff per round relative to anonymity. Furthermore, we also show that the correlation between players' ranks and the usage of strategies (cooperation, defection, or punishment) underwent a fundamental shift, whereby more prosocial actions are rewarded with a better ranking under onymity. Our findings prove that reducing anonymity is a valid promoter of cooperation, leading to higher payoffs for cooperators and thus suppressing an incentive-anonymity-that would ultimately favor defection.},
}
@article {pmid28419349,
year = {2017},
author = {Warner, MR and Mikheyev, AS and Linksvayer, TA},
title = {Genomic Signature of Kin Selection in an Ant with Obligately Sterile Workers.},
journal = {Molecular biology and evolution},
volume = {34},
number = {7},
pages = {1780-1787},
doi = {10.1093/molbev/msx123},
pmid = {28419349},
issn = {1537-1719},
mesh = {Animals ; Ants/*genetics ; Behavior, Animal ; Biological Evolution ; Evolution, Molecular ; Family ; Genetics, Population/methods ; Genomics ; Infertility/genetics ; Metagenomics/methods ; Phenotype ; Reproduction/genetics ; Selection, Genetic/*genetics ; Social Behavior ; },
abstract = {Kin selection is thought to drive the evolution of cooperation and conflict, but the specific genes and genome-wide patterns shaped by kin selection are unknown. We identified thousands of genes associated with the sterile ant worker caste, the archetype of an altruistic phenotype shaped by kin selection, and then used population and comparative genomic approaches to study patterns of molecular evolution at these genes. Consistent with population genetic theoretical predictions, worker-upregulated genes experienced reduced selection compared with genes upregulated in reproductive castes. Worker-upregulated genes included more taxonomically restricted genes, indicating that the worker caste has recruited more novel genes, yet these genes also experienced reduced selection. Our study identifies a putative genomic signature of kin selection and helps to integrate emerging sociogenomic data with longstanding social evolution theory.},
}
@article {pmid28417004,
year = {2017},
author = {Jackson, CR and Groom, RJ and Jordan, NR and McNutt, JW},
title = {The effect of relatedness and pack size on territory overlap in African wild dogs.},
journal = {Movement ecology},
volume = {5},
number = {},
pages = {10},
doi = {10.1186/s40462-017-0099-8},
pmid = {28417004},
issn = {2051-3933},
abstract = {BACKGROUND: Spacing patterns mediate competitive interactions between conspecifics, ultimately increasing fitness. The degree of territorial overlap between neighbouring African wild dog (Lycaon pictus) packs varies greatly, yet the role of factors potentially affecting the degree of overlap, such as relatedness and pack size, remain unclear. We used movement data from 21 wild dog packs to calculate the extent of territory overlap (20 dyads).

RESULTS: On average, unrelated neighbouring packs had low levels of overlap restricted to the peripheral regions of their 95% utilisation kernels. Related neighbours had significantly greater levels of peripheral overlap. Only one unrelated dyad included overlap between 75%-75% kernels, but no 50%-50% kernels overlapped. However, eight of 12 related dyads overlapped between their respective 75% kernels and six between the frequented 50% kernels. Overlap between these more frequented kernels confers a heightened likelihood of encounter, as the mean utilisation intensity per unit area within the 50% kernels was 4.93 times greater than in the 95% kernels, and 2.34 times greater than in the 75% kernels. Related packs spent significantly more time in their 95% kernel overlap zones than did unrelated packs. Pack size appeared to have little effect on overlap between related dyads, yet among unrelated neighbours larger packs tended to overlap more onto smaller packs' territories. However, the true effect is unclear given that the model's confidence intervals overlapped zero.

CONCLUSIONS: Evidence suggests that costly intraspecific aggression is greatly reduced between related packs. Consequently, the tendency for dispersing individuals to establish territories alongside relatives, where intensively utilised portions of ranges regularly overlap, may extend kin selection and inclusive fitness benefits from the intra-pack to inter-pack level. This natural spacing system can affect survival parameters and the carrying capacity of protected areas, having important management implications for intensively managed populations of this endangered species.},
}
@article {pmid28410027,
year = {2017},
author = {Kuijper, B and Johnstone, RA},
title = {How Sex-Biased Dispersal Affects Sexual Conflict over Care.},
journal = {The American naturalist},
volume = {189},
number = {5},
pages = {501-514},
doi = {10.1086/691330},
pmid = {28410027},
issn = {1537-5323},
mesh = {*Animal Distribution ; Animals ; *Conflict (Psychology) ; Female ; Male ; *Maternal Behavior ; Models, Biological ; *Paternal Behavior ; Reproduction ; Sex Factors ; },
abstract = {Existing models of parental investment have mainly focused on interactions at the level of the family and have paid much less attention to the impact of population-level processes. Here we extend classical models of parental care to assess the impact of population structure and limited dispersal. We find that sex differences in dispersal substantially affect the amount of care provided by each parent, with the more philopatric sex providing the majority of care to young. This effect is most pronounced in highly viscous populations: in such cases, when classical models would predict stable biparental care, inclusion of a modest sex difference in dispersal leads to uniparental care by the philopatric sex. In addition, mating skew also affects sex differences in parental investment, with the more numerous sex providing most of the care. However, the effect of mating skew holds only when parents care for their own offspring. When individuals breed communally, we recover the previous finding that the more philopatric sex provides most of the care even when it is the rarer sex. We conclude that sex-biased dispersal is likely to be an important yet currently overlooked driver of sex differences in parental care.},
}
@article {pmid28360453,
year = {2017},
author = {Ruiz-Lambides, AV and Weiß, BM and Kulik, L and Stephens, C and Mundry, R and Widdig, A},
title = {Long-term analysis on the variance of extra-group paternities in rhesus macaques.},
journal = {Behavioral ecology and sociobiology},
volume = {71},
number = {4},
pages = {67},
doi = {10.1007/s00265-017-2291-7},
pmid = {28360453},
issn = {0340-5443},
support = {P40 OD012217/OD/NIH HHS/United States ; },
abstract = {ABSTRACT: Extra-group paternity (EGP) has been described in various mammalian species; however, little is known about which factors contribute to the variation in EGP, as the majority of studies were restricted in time and the number of groups considered. Using longitudinal demographic and genetic data, we aim to investigate which factors predict rates of EGP in the free-ranging rhesus macaque population of Cayo Santiago, Puerto Rico (USA). Of the 1649 infants considered which were born into six social groups over 9 years, we identified an average of 16% of infants resulting from EGPs. We tested the influence of group size, breeding group sex ratio, female reproductive synchrony, and group instability on the occurrence of EGPs. Our results suggest a tendency for EGPs to increase as the proportion of females increased in larger groups, but no such effect in smaller groups. Furthermore, as group instability and female reproductive synchrony decreased, the number of EGPs tended to increase. Our results support the hypothesis that group structure affects the occurrence of EGPs, which might be mediated by male mating opportunities, male monopolization potential, and/or female choice.

SIGNIFICANCE STATEMENT: In several species, both sexes seek alternative reproductive strategies to enhance their reproductive success. For instance, females may pursue EGPs to potentially increase genetic compatibility with males, or males may seek EGPs to improve their mating opportunities. Our longitudinal analysis, including demographic and genetic data over 9 years of six social groups of rhesus macaques, revealed high variation in the occurrence of EGPs across groups and years, and this variation tended to depend on group characteristics such as breeding group size, sex ratio, female synchrony, and group instability. The data suggest that group structure affects the number of EGPs in this group-living primate. Our results show that EGPs can affect the distribution of paternity within social groups and should be taken into account when assessing reproductive success.},
}
@article {pmid28345048,
year = {2017},
author = {Łukasiewicz, A and Szubert-Kruszyńska, A and Radwan, J},
title = {Kin selection promotes female productivity and cooperation between the sexes.},
journal = {Science advances},
volume = {3},
number = {3},
pages = {e1602262},
doi = {10.1126/sciadv.1602262},
pmid = {28345048},
issn = {2375-2548},
mesh = {Acaridae/*genetics ; Animals ; *Biological Evolution ; Female ; Male ; *Models, Biological ; *Quantitative Trait, Heritable ; Reproduction/physiology ; *Selection, Genetic ; },
abstract = {Hamilton's theory of kin selection explains the evolution of costly traits that benefit other individuals by highlighting the fact that passing genes to offspring is not the only way of increasing the representation of those genes in subsequent generations: Genes are also shared with other classes of relatives. Consequently, any heritable trait that affects fitness of relatives should respond to kin selection. We tested this core prediction of kin selection theory by letting bulb mites (Rhizoglyphus robini) evolve in populations structured into groups of relatives or nonrelatives during the reproductive phase of the life cycle. In accordance with predictions derived from kin selection theory, we found that evolution in groups of relatives resulted in increased female reproductive output. This increase at least partly results from the evolution of male traits that elevate their partners' fecundity. Our results highlight the power and universality of kin selection.},
}
@article {pmid28328991,
year = {2017},
author = {Dušek, A and Bartoš, L and Sedláček, F},
title = {Pre-breeding food restriction promotes the optimization of parental investment in house mice, Mus musculus.},
journal = {PloS one},
volume = {12},
number = {3},
pages = {e0173985},
doi = {10.1371/journal.pone.0173985},
pmid = {28328991},
issn = {1932-6203},
mesh = {Animals ; Body Weight/physiology ; Breeding/methods ; Female ; Food ; Lactation/physiology ; Litter Size/physiology ; Mice ; Mice, Inbred ICR ; Parents ; Pregnancy ; Reproduction/*physiology ; Weaning ; },
abstract = {Litter size is one of the most reliable state-dependent life-history traits that indicate parental investment in polytocous (litter-bearing) mammals. The tendency to optimize litter size typically increases with decreasing availability of resources during the period of parental investment. To determine whether this tactic is also influenced by resource limitations prior to reproduction, we examined the effect of experimental, pre-breeding food restriction on the optimization of parental investment in lactating mice. First, we investigated the optimization of litter size in 65 experimental and 72 control families (mothers and their dependent offspring). Further, we evaluated pre-weaning offspring mortality, and the relationships between maternal and offspring condition (body weight), as well as offspring mortality, in 24 experimental and 19 control families with litter reduction (the death of one or more offspring). Assuming that pre-breeding food restriction would signal unpredictable food availability, we hypothesized that the optimization of parental investment would be more effective in the experimental rather than in the control mice. In comparison to the controls, the experimental mice produced larger litters and had a more selective (size-dependent) offspring mortality and thus lower litter reduction (the proportion of offspring deaths). Selective litter reduction helped the experimental mothers to maintain their own optimum condition, thereby improving the condition and, indirectly, the survival of their remaining offspring. Hence, pre-breeding resource limitations may have facilitated the mice to optimize their inclusive fitness. On the other hand, in the control females, the absence of environmental cues indicating a risky environment led to "maternal optimism" (overemphasizing good conditions at the time of breeding), which resulted in the production of litters of super-optimal size and consequently higher reproductive costs during lactation, including higher offspring mortality. Our study therefore provides the first evidence that pre-breeding food restriction promotes the optimization of parental investment, including offspring number and developmental success.},
}
@article {pmid28322868,
year = {2017},
author = {Ohtsuki, H and Wakano, JY and Kobayashi, Y},
title = {Inclusive fitness analysis of cumulative cultural evolution in an island-structured population.},
journal = {Theoretical population biology},
volume = {115},
number = {},
pages = {13-23},
doi = {10.1016/j.tpb.2017.03.001},
pmid = {28322868},
issn = {1096-0325},
mesh = {*Biological Evolution ; *Cultural Evolution ; *Genetic Fitness ; Humans ; Learning ; Reproduction ; },
abstract = {The success of humans on the globe is largely supported by our cultural excellence. Our culture is cumulative, meaning that it is improved from generation to generation. Previous works have revealed that two modes of learning, individual learning and social learning, play pivotal roles in the accumulation of culture. However, under the trade-off between learning and reproduction, one's investment into learning is easily exploited by those who copy the knowledge of skillful individuals and selfishly invest more efforts in reproduction. It has been shown that in order to prevent such a breakdown, the rate of vertical transmission (i.e. transmission from parents to their offspring) of culture must be unrealistically close to one. Here we investigate what if the population is spatially structured. In particular, we hypothesize that spatial structure should favor highly cumulative culture through endogenously arising high kinship. We employ Wright's island model and assume that cultural transmission occurs within a local island. Our inclusive fitness analysis reveals combined effects of direct fitness of the actor, indirect fitness through relatives in the current generation, and indirect fitness through relatives in future generations. The magnitude of those indirect benefits is measured by intergenerational coefficients of genetic relatedness. Our result suggests that the introduction of spatial structure raises the stationary level of culture in the population, but that the extent of its improvement compared with a well-mixed population is marginal unless spatial localization is extreme. Overall, our model implies that we need an alternative mechanism to explain highly cumulative culture of modern humans.},
}
@article {pmid28298744,
year = {2017},
author = {Welch, JJ},
title = {What's wrong with evolutionary biology?.},
journal = {Biology & philosophy},
volume = {32},
number = {2},
pages = {263-279},
doi = {10.1007/s10539-016-9557-8},
pmid = {28298744},
issn = {0169-3867},
abstract = {There have been periodic claims that evolutionary biology needs urgent reform, and this article tries to account for the volume and persistence of this discontent. It is argued that a few inescapable properties of the field make it prone to criticisms of predictable kinds, whether or not the criticisms have any merit. For example, the variety of living things and the complexity of evolution make it easy to generate data that seem revolutionary (e.g. exceptions to well-established generalizations, or neglected factors in evolution), and lead to disappointment with existing explanatory frameworks (with their high levels of abstraction, and limited predictive power). It is then argued that special discontent stems from misunderstandings and dislike of one well-known but atypical research programme: the study of adaptive function, in the tradition of behavioural ecology. To achieve its goals, this research needs distinct tools, often including imaginary agency, and a partial description of the evolutionary process. This invites mistaken charges of narrowness and oversimplification (which come, not least, from researchers in other subfields), and these chime with anxieties about human agency and overall purpose. The article ends by discussing several ways in which calls to reform evolutionary biology actively hinder progress in the field.},
}
@article {pmid28295032,
year = {2017},
author = {Rode, NO and Soroye, P and Kassen, R and Rundle, HD},
title = {Air-borne genotype by genotype indirect genetic effects are substantial in the filamentous fungus Aspergillus nidulans.},
journal = {Heredity},
volume = {119},
number = {1},
pages = {1-7},
doi = {10.1038/hdy.2017.9},
pmid = {28295032},
issn = {1365-2540},
mesh = {*Air Microbiology ; Aspergillus nidulans/*genetics/growth & development ; *Genetic Fitness ; *Genotype ; Microbial Interactions/*genetics ; Models, Genetic ; Phenotype ; },
abstract = {Genotype by genotype indirect genetic effects (G × G IGEs) occur when the phenotype of an individual is influenced by an interaction between its own genotype and those of neighbour individuals. Little is known regarding the relative importance of G × G IGEs compared with other forms of direct and indirect genetic effects. We quantified the relative importance of IGEs in the filamentous fungus Aspergillus nidulans, a species in which IGEs are likely to be important as air-borne social interactions are known to affect growth. We used a collection of distantly related wild isolates, lab strains and a set of closely related mutation accumulation lines to estimate the contribution of direct and indirect genetic effects on mycelium growth rate, a key fitness component. We found that indirect genetic effects were dominated by G × G IGEs that occurred primarily between a focal genotype and its immediate neighbour within a vertical stack, and these accounted for 11% of phenotypic variation. These results indicate that G × G IGEs may be substantial, at least in some systems, and that the evolutionary importance of these interactions may be underappreciated, especially in microbes. We advocate for a wider use of the IGE framework in both applied (for example, choice of varietal mixtures in plant breeding) and evolutionary genetics (kin selection/kin competition studies).},
}
@article {pmid28280587,
year = {2017},
author = {Murphy, GP and Van Acker, R and Rajcan, I and Swanton, CJ},
title = {Identity recognition in response to different levels of genetic relatedness in commercial soya bean.},
journal = {Royal Society open science},
volume = {4},
number = {1},
pages = {160879},
doi = {10.1098/rsos.160879},
pmid = {28280587},
issn = {2054-5703},
abstract = {Identity recognition systems allow plants to tailor competitive phenotypes in response to the genetic relatedness of neighbours. There is limited evidence for the existence of recognition systems in crop species and whether they operate at a level that would allow for identification of different degrees of relatedness. Here, we test the responses of commercial soya bean cultivars to neighbours of varying genetic relatedness consisting of other commercial cultivars (intraspecific), its wild progenitor Glycine soja, and another leguminous species Phaseolus vulgaris (interspecific). We found, for the first time to our knowledge, that a commercial soya bean cultivar, OAC Wallace, showed identity recognition responses to neighbours at different levels of genetic relatedness. OAC Wallace showed no response when grown with other commercial soya bean cultivars (intra-specific neighbours), showed increased allocation to leaves compared with stems with wild soya beans (highly related wild progenitor species), and increased allocation to leaves compared with stems and roots with white beans (interspecific neighbours). Wild soya bean also responded to identity recognition but these responses involved changes in biomass allocation towards stems instead of leaves suggesting that identity recognition responses are species-specific and consistent with the ecology of the species. In conclusion, elucidating identity recognition in crops may provide further knowledge into mechanisms of crop competition and the relationship between crop density and yield.},
}
@article {pmid28233388,
year = {2017},
author = {Erb, WM and Porter, LM},
title = {Mother's little helpers: What we know (and don't know) about cooperative infant care in callitrichines.},
journal = {Evolutionary anthropology},
volume = {26},
number = {1},
pages = {25-37},
doi = {10.1002/evan.21516},
pmid = {28233388},
issn = {1520-6505},
mesh = {Animals ; Anthropology, Physical ; *Biological Evolution ; Callitrichinae/*physiology ; *Cooperative Behavior ; Female ; Male ; *Maternal Behavior ; Selection, Genetic ; },
abstract = {Since Darwin (), scientists have been puzzled by how behaviors that impose fitness costs on helpers while benefiting their competitors could evolve through natural selection. Hamilton's () theory of inclusive fitness provided an explanation by showing how cooperative behaviors could be adaptive if directed at closely related kin. Recent studies, however, have begun to question whether kin selection is sufficient to explain cooperative behavior in some species (Bergmüller, Johnstone, Russell, & Bshary,). Many researchers have instead emphasized the importance of direct fitness benefits for helpers in the evolution of cooperative breeding systems. Furthermore, individuals can vary in who, when, and how much they help, and the factors that affect this variation are poorly understood (Cockburn, ; Heinsohn,). Cooperative breeders thus provide excellent models for the study of evolutionary theories of cooperation and conflict (Cant,).},
}
@article {pmid28229624,
year = {2017},
author = {Gray, PB and Brogdon, E},
title = {Do Step- and Biological Grandparents Show Differences in Investment and Emotional Closeness With Their Grandchildren?.},
journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior},
volume = {15},
number = {1},
pages = {1474704917694367},
doi = {10.1177/1474704917694367},
pmid = {28229624},
issn = {1474-7049},
mesh = {Adult ; Female ; Grandparents/*psychology ; Humans ; *Intergenerational Relations ; Male ; },
abstract = {Human children are raised by a variety of caregivers including grandparents. A few studies have assessed potential differences in direct caregiving, financial expenditures, and emotional closeness between biological and step-grandparents. Drawing upon kin selection theory, we hypothesized that step-grandparents would provide less care and be less emotionally close to grandchildren than would biological grandparents. A sample of 341 heterosexual U.S. adults 25-35 years of age in a long-term partnership and with a biological child 5 years of age or younger were recruited via Amazon Mechanical Turk. Subjects provided sociodemographic information and answered questions about the dynamics between their own parent/stepparent and their own youngest biological child (hence, biological/step-grandparenting dynamics). Main analyses were restricted to within-subject comparisons. Results showed that biological grandmothers provided more direct childcare, financial expenditures, and had more emotionally close relationships with grandchildren than did step-grandmothers. Biological grandfathers provided less direct care and had less emotionally close relationships than step-grandfathers but did not exhibit differences in financial expenditures. Biological grandmothers provided more direct care, financial investment, and were more emotionally close to the referential grandchild than were biological grandfathers. Step-grandfathers were more emotionally close and more often played with grandchildren than step-grandmothers. These findings partially support kin selection theory. We discuss the relevance of factors such as competing demands on grandmothers' investment in biological and step-grandchildren and grandfathering serving in part as mating effort. Sex differences in biological grandparenting also mirror those in parenting. We suggest directions for future research, including on grandfathers, particularly in patrilineal societies.},
}
@article {pmid28202814,
year = {2017},
author = {Vedder, O and Zhang, H and Bouwhuis, S},
title = {Early mortality saves energy: estimating the energetic cost of excess offspring in a seabird.},
journal = {Proceedings. Biological sciences},
volume = {284},
number = {1849},
pages = {},
doi = {10.1098/rspb.2016.2724},
pmid = {28202814},
issn = {1471-2954},
mesh = {Animals ; Charadriiformes/*metabolism ; *Clutch Size ; Energy Intake ; *Mortality ; },
abstract = {Offspring are often produced in excess as insurance against stochastic events or unpredictable resources. This strategy may result in high early-life mortality, yet age-specific mortality before offspring independence and its associated costs have rarely been quantified. In this study, we modelled age-specific survival from hatching to fledging using 24 years of data on hatching order (HO), growth and age of mortality of more than 15 000 common tern (Sterna hirundo) chicks. We found that mortality peaked directly after hatching, after which it declined rapidly. Mortality hazard was best described with the Gompertz function, and was higher with later HO, mainly due to differences in baseline mortality hazard, rather than age-dependent mortality. Based on allometric mass-metabolism relationships and detailed growth curves of starving chicks, we estimated that the average metabolizable energy intake of non-fledged chicks was only 8.7% of the metabolizable energy intake of successful chicks during the nestling phase. Although 54% of hatchlings did not fledge, our estimates suggest them to have consumed only 9.3% of the total energy consumption of all hatched chicks in the population before fledging. We suggest that rapid mortality of excess offspring is part of an adaptive brood reduction strategy to the benefit of the parents.},
}
@article {pmid28107054,
year = {2017},
author = {Andersson, M},
title = {Helping Relatives Survive and Reproduce: Inclusive Fitness and Reproductive Value in Brood Parasitism.},
journal = {The American naturalist},
volume = {189},
number = {2},
pages = {138-152},
doi = {10.1086/689991},
pmid = {28107054},
issn = {1537-5323},
mesh = {Animals ; Birds ; Female ; *Host-Parasite Interactions ; *Nesting Behavior ; *Reproduction ; Symbiosis ; },
abstract = {Costly help can raise a relative's reproduction, survival, and reproductive value and increase the inclusive fitness of the donor of help. Donor fitness is explored here in conspecific brood parasitism. In this alternative reproductive tactic, some females, "parasites," lay eggs in nests of other females of the same species, "hosts," suppliers of help that alone take care of the offspring. Modeling shows that hosts can gain inclusive fitness if parasitized by relatives whose reproduction or survival is thereby increased. These predictions are explored in waterfowl with frequent brood parasitism, female-biased philopatry, and neighbor relatedness. Approximate estimates based on waterfowl reproductive and life-history data show that host inclusive-fitness gain is often possible with related parasites. The largest gains can be achieved through increased reproduction, but gain is also possible through higher survival of parasites that avoid increased predation and other risks of nesting. Inclusive fitness depends on parasite reproductive value and can be highest for a host parasitized by her mother and for old, senescent hosts with low fecundity, helping young related parasites. These results and observed levels of host-parasite relatedness suggest that being "parasitized" in waterfowl is sometimes neutral or even advantageous because of inclusive-fitness benefits, contributing to evolution of frequent conspecific brood parasitism in this group.},
}
@article {pmid28089514,
year = {2017},
author = {Croft, DP and Johnstone, RA and Ellis, S and Nattrass, S and Franks, DW and Brent, LJ and Mazzi, S and Balcomb, KC and Ford, JK and Cant, MA},
title = {Reproductive Conflict and the Evolution of Menopause in Killer Whales.},
journal = {Current biology : CB},
volume = {27},
number = {2},
pages = {298-304},
doi = {10.1016/j.cub.2016.12.015},
pmid = {28089514},
issn = {1879-0445},
mesh = {Animals ; *Biological Evolution ; Female ; *Menopause ; Reproduction ; Whale, Killer/*physiology ; },
abstract = {Why females of some species cease ovulation prior to the end of their natural lifespan is a long-standing evolutionary puzzle [1-4]. The fitness benefits of post-reproductive helping could in principle select for menopause [1, 2, 5], but the magnitude of these benefits appears insufficient to explain the timing of menopause [6-8]. Recent theory suggests that the cost of inter-generational reproductive conflict between younger and older females of the same social unit is a critical missing term in classical inclusive fitness calculations (the "reproductive conflict hypothesis" [6, 9]). Using a unique long-term dataset on wild resident killer whales, where females can live decades after their final parturition, we provide the first test of this hypothesis in a non-human animal. First, we confirm previous theoretical predictions that local relatedness increases with female age up to the end of reproduction. Second, we construct a new evolutionary model and show that given these kinship dynamics, selection will favor younger females that invest more in competition, and thus have greater reproductive success, than older females (their mothers) when breeding at the same time. Third, we test this prediction using 43 years of individual-based demographic data in resident killer whales and show that when mothers and daughters co-breed, the mortality hazard of calves from older-generation females is 1.7 times that of calves from younger-generation females. Intergenerational conflict combined with the known benefits conveyed to kin by post-reproductive females can explain why killer whales have evolved the longest post-reproductive lifespan of all non-human animals.},
}
@article {pmid28079112,
year = {2017},
author = {Lewin-Epstein, O and Aharonov, R and Hadany, L},
title = {Microbes can help explain the evolution of host altruism.},
journal = {Nature communications},
volume = {8},
number = {},
pages = {14040},
doi = {10.1038/ncomms14040},
pmid = {28079112},
issn = {2041-1723},
mesh = {*Altruism ; *Biological Evolution ; *Microbiota ; *Models, Genetic ; },
abstract = {The evolution of altruistic behaviour, which is costly to the donor but beneficial for the recipient, is among the most intriguing questions in evolutionary biology. Several theories have been proposed to explain it, including kin selection, group selection and reciprocity. Here we propose that microbes that manipulate their hosts to act altruistically could be favoured by selection, and may play a role in the widespread occurrence of altruism. Using computational models, we find that microbe-induced altruism can explain the evolution of host altruistic behaviour under wider conditions than host-centred theories, including in a fully mixed host population, without repeating interactions or individual recognition. Our results suggest that factors such as antibiotics that kill microbes might negatively affect cooperation in a wide range of organisms.},
}
@article {pmid28066387,
year = {2016},
author = {Zhang, Z and Claessen, D and Rozen, DE},
title = {Understanding Microbial Divisions of Labor.},
journal = {Frontiers in microbiology},
volume = {7},
number = {},
pages = {2070},
doi = {10.3389/fmicb.2016.02070},
pmid = {28066387},
issn = {1664-302X},
abstract = {Divisions of labor are ubiquitous in nature and can be found at nearly every level of biological organization, from the individuals of a shared society to the cells of a single multicellular organism. Many different types of microbes have also evolved a division of labor among its colony members. Here we review several examples of microbial divisions of labor, including cases from both multicellular and unicellular microbes. We first discuss evolutionary arguments, derived from kin selection, that allow divisions of labor to be maintained in the face of non-cooperative cheater cells. Next we examine the widespread natural variation within species in their expression of divisions of labor and compare this to the idea of optimal caste ratios in social insects. We highlight gaps in our understanding of microbial caste ratios and argue for a shift in emphasis from understanding the maintenance of divisions of labor, generally, to instead focusing on its specific ecological benefits for microbial genotypes and colonies. Thus, in addition to the canonical divisions of labor between, e.g., reproductive and vegetative tasks, we may also anticipate divisions of labor to evolve to reduce the costly production of secondary metabolites or secreted enzymes, ideas we consider in the context of streptomycetes. The study of microbial divisions of labor offers opportunities for new experimental and molecular insights across both well-studied and novel model systems.},
}
@article {pmid28057829,
year = {2017},
author = {Matsuura, K},
title = {Evolution of the asexual queen succession system and its underlying mechanisms in termites.},
journal = {The Journal of experimental biology},
volume = {220},
number = {Pt 1},
pages = {63-72},
doi = {10.1242/jeb.142547},
pmid = {28057829},
issn = {1477-9145},
mesh = {Animals ; *Biological Evolution ; Female ; Genomic Imprinting ; Isoptera/genetics/*physiology ; Male ; Parthenogenesis ; Pheromones/metabolism ; Reproduction ; *Reproduction, Asexual ; Sex Ratio ; Sexual Behavior, Animal ; },
abstract = {One major advantage of sexual reproduction over asexual reproduction is its promotion of genetic variation, although it reduces the genetic contribution to offspring. Queens of social insects double their contribution to the gene pool, while overuse of asexual reproduction may reduce the ability of the colony to adapt to environmental stress because of the loss of genetic diversity. Recent studies have revealed that queens of some termite species can solve this tradeoff by using parthenogenesis to produce the next generation of queens and sexual reproduction to produce other colony members. This reproductive system, known as asexual queen succession (AQS), has been identified in the subterranean termites Reticulitermes speratus, Reticulitermes virginicus and Reticulitermes lucifugus and in the Neotropical higher termites Embiratermes neotenicus and Cavitermes tuberosus The studies presented here have uncovered the unusual modes of reproduction in termites and have aimed to identify their underlying mechanisms. The study of AQS, the mixed use of sexual and asexual reproduction, is of fundamental importance as it may provide a key to solve the evolutionary paradox of sex.},
}
@article {pmid28035273,
year = {2016},
author = {Procter, DS and Cottrell, JE and Watts, K and A'Hara, SW and Hofreiter, M and Robinson, EJ},
title = {Does cooperation mean kinship between spatially discrete ant nests?.},
journal = {Ecology and evolution},
volume = {6},
number = {24},
pages = {8846-8856},
doi = {10.1002/ece3.2590},
pmid = {28035273},
issn = {2045-7758},
abstract = {Eusociality is one of the most complex forms of social organization, characterized by cooperative and reproductive units termed colonies. Altruistic behavior of workers within colonies is explained by inclusive fitness, with indirect fitness benefits accrued by helping kin. Members of a social insect colony are expected to be more closely related to one another than they are to other conspecifics. In many social insects, the colony can extend to multiple socially connected but spatially separate nests (polydomy). Social connections, such as trails between nests, promote cooperation and resource exchange, and we predict that workers from socially connected nests will have higher internest relatedness than those from socially unconnected, and noncooperating, nests. We measure social connections, resource exchange, and internest genetic relatedness in the polydomous wood ant Formica lugubris to test whether (1) socially connected but spatially separate nests cooperate, and (2) high internest relatedness is the underlying driver of this cooperation. Our results show that socially connected nests exhibit movement of workers and resources, which suggests they do cooperate, whereas unconnected nests do not. However, we find no difference in internest genetic relatedness between socially connected and unconnected nest pairs, both show high kinship. Our results suggest that neighboring pairs of connected nests show a social and cooperative distinction, but no genetic distinction. We hypothesize that the loss of a social connection may initiate ecological divergence within colonies. Genetic divergence between neighboring nests may build up only later, as a consequence rather than a cause of colony separation.},
}
@article {pmid28028377,
year = {2016},
author = {Preston, SA and Briskie, JV and Hatchwell, BJ},
title = {Adult helpers increase the recruitment of closely related offspring in the cooperatively breeding rifleman.},
journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology},
volume = {27},
number = {6},
pages = {1617-1626},
doi = {10.1093/beheco/arw087},
pmid = {28028377},
issn = {1045-2249},
abstract = {Indirect fitness benefits gained through kin-selected helping are widely invoked to explain the evolution of cooperative breeding behavior in birds. However, the impact of helpers on productivity of helped broods can be difficult to determine if the effects are confounded by territory quality or if the benefit of helpers is apparent only in the long term. In riflemen Acanthisitta chloris, helping and group membership are effectively decoupled as adult helpers are individuals that have dispersed from their natal territory and live independently from breeders in "kin neighborhoods." Nevertheless, helpers direct their care toward close relatives, suggesting that helping provides indirect fitness benefits. The aim of this study was to examine the benefits of helpers to recipient offspring in the rifleman, investigating both short- and long-term effects. The total amount of food delivered to nestlings in helped broods was greater than that received by broods without helpers. This did not result in any short-term increase in nestling mass or nestling body condition nor was there any reduction in length of the nestling period at helped nests. However, helpers were associated with a significant increase in juvenile recruitment, with twice the proportion of fledglings surviving to the next breeding season from helped broods relative to unhelped broods. Thus, helpers gain indirect fitness by improving the survival of kin, and in contrast to a previous study of riflemen, we conclude that kin selection has played a key role in the evolution of cooperative breeding in this species.},
}
@article {pmid28018027,
year = {2017},
author = {Widdig, A and Muniz, L and Minkner, M and Barth, Y and Bley, S and Ruiz-Lambides, A and Junge, O and Mundry, R and Kulik, L},
title = {Low incidence of inbreeding in a long-lived primate population isolated for 75 years.},
journal = {Behavioral ecology and sociobiology},
volume = {71},
number = {1},
pages = {18},
doi = {10.1007/s00265-016-2236-6},
pmid = {28018027},
issn = {0340-5443},
support = {P40 OD012217/OD/NIH HHS/United States ; },
abstract = {ABSTRACT: When close relatives mate, offspring are expected to suffer fitness consequences due to inbreeding depression. Inbreeding has previously been quantified in two ways: using a sufficiently large panel of markers or deep and complete pedigrees over several generations. However, the application of both approaches is still limited by the challenge of compiling such data for species with long generation times, such as primates. Here, we assess inbreeding in rhesus macaques living on Cayo Santiago (Puerto Rico), a population genetically isolated since 1938, but descendant of a large set of presumably unrelated founders. Using comprehensive genetic data, we calculated inbreeding coefficients (F) for 2669 individuals with complete three generation pedigrees and 609 individuals with complete four generation pedigrees. We found that 0.79 and 7.39% of individuals had an F > 0 when using data from three and four generation pedigrees, respectively. No evidence of an increase in inbreeding over the study period (up to 23 years) was found. Furthermore, the observed mean relatedness of breeding pairs differed significantly from the distribution of parental relatedness expected as simulated based on previous reproductive data, suggesting that kin generally avoid breeding with each other. Finally, inbreeding was not a predictor of early mortality measured as survival until weaning and sexual maturation, respectively. Our results remain consistent with three estimators of inbreeding (standardized heterozygosity, internal relatedness, and homozygosity by loci) using up to 42 highly polymorphic microsatellites for the same set of individuals. Together, our results demonstrate that close inbreeding may not be prevalent even in populations isolated over long periods when mechanisms of inbreeding avoidance can operate.

SIGNIFICANCE STATEMENT: When close relatives mate, offspring may suffer from such inbreeding, e.g., via lower survival and/or fertility. Using (i) a large panel of genetic markers and (ii) complete three or four generation pedigrees, respectively, we show that incidences of inbreeding in a long-lived primate population are rare, even after genetic isolation for 75 years. Moreover, our simulations suggest that kin in our population generally avoid breeding with each other. Finally, the few inbred individuals detected in our large sample did not suffer from lower survival. Given that many animal species face dramatic habitat loss combined with critical population declines, our study provides important implications for conservation biology in general and for population management in particular.},
}
@article {pmid28012185,
year = {2017},
author = {Taylor, P},
title = {Inclusive fitness in finite populations-effects of heterogeneity and synergy.},
journal = {Evolution; international journal of organic evolution},
volume = {71},
number = {3},
pages = {508-525},
doi = {10.1111/evo.13160},
pmid = {28012185},
issn = {1558-5646},
mesh = {Game Theory ; *Gene Frequency ; *Genetic Fitness ; Models, Genetic ; Population Density ; *Selection, Genetic ; },
abstract = {I review recent results concerning the relationship between the inclusive fitness (IF) effect and standard measures of allele fitness in a finite-population, with attention to the effect of heterogeneity in population structure and nonadditive fitness effects. In both cases, existing theoretical work is somewhat technical and I try to provide a more transparent account. In a heterogeneous population it is known that inclusive fitness will generally fail to incorporate the effects of selection on the distribution of alleles among states unless a reproductive-value weighting is used. But even given that, recent work shows that under certain updating rules, the IF effect can fail to be equivalent to standard measures such as fixation probability. In terms of synergistic fitness effects, I review the result that in the finite population model, the IF effect can be calculated using only "additive" relatedness coefficients so that computational difficulties found in the infinite-population model do not arise. In my own work, there is an interaction here in that my 2012 work on synergy with Maciejewski made an assumption about inclusive fitness that my 2014 work on heterogeneity with Tarnita showed to be wrong. I include (Appendix C) a corrected argument for the 2012 result.},
}
@article {pmid27991659,
year = {2017},
author = {Faria, GS and Varela, SA and Gardner, A},
title = {Sexual selection modulates genetic conflicts and patterns of genomic imprinting.},
journal = {Evolution; international journal of organic evolution},
volume = {71},
number = {3},
pages = {526-540},
doi = {10.1111/evo.13153},
pmid = {27991659},
issn = {1558-5646},
mesh = {Alleles ; *Animal Distribution ; Animals ; Female ; *Genetic Fitness ; *Genomic Imprinting ; Invertebrates/*genetics/physiology ; Male ; Models, Genetic ; Population Density ; Selection, Genetic ; Sex Factors ; Vertebrates/*genetics/physiology ; },
abstract = {Recent years have seen a surge of interest in linking the theories of kin selection and sexual selection. In particular, there is a growing appreciation that kin selection, arising through demographic factors such as sex-biased dispersal, may modulate sexual conflicts, including in the context of male-female arms races characterized by coevolutionary cycles. However, evolutionary conflicts of interest need not only occur between individuals, but may also occur within individuals, and sex-specific demography is known to foment such intragenomic conflict in relation to social behavior. Whether and how this logic holds in the context of sexual conflict-and, in particular, in relation to coevolutionary cycles-remains obscure. We develop a kin-selection model to investigate the interests of different genes involved in sexual and intragenomic conflict, and we show that consideration of these conflicting interests yields novel predictions concerning parent-of-origin specific patterns of gene expression and the detrimental effects of different classes of mutation and epimutation at loci underpinning sexually selected phenotypes.},
}
@article {pmid27990255,
year = {2016},
author = {Newman, SJ and Eyre, S and Kimble, CH and Arcos-Burgos, M and Hogg, C and Easteal, S},
title = {Reproductive success is predicted by social dynamics and kinship in managed animal populations.},
journal = {F1000Research},
volume = {5},
number = {},
pages = {870},
doi = {10.12688/f1000research.8713.1},
pmid = {27990255},
issn = {2046-1402},
abstract = {Kin and group interactions are important determinants of reproductive success in many species. Their optimization could, therefore, potentially improve the productivity and breeding success of managed populations used for agricultural and conservation purposes. Here we demonstrate this potential using a novel approach to measure and predict the effect of kin and group dynamics on reproductive output in a well-known species, the meerkat Suricata suricatta. Variation in social dynamics predicts 30% of the individual variation in reproductive success of this species in managed populations, and accurately forecasts reproductive output at least two years into the future. Optimization of social dynamics in captive meerkat populations doubles their projected reproductive output. These results demonstrate the utility of a quantitative approach to breeding programs informed by social and kinship dynamics. They suggest that this approach has great potential for improvements in the management of social endangered and agricultural species.},
}
@article {pmid27987088,
year = {2017},
author = {VanderLaan, DP and Petterson, LJ and Vasey, PL},
title = {Elevated Kin-Directed Altruism Emerges in Childhood and Is Linked to Feminine Gender Expression in Samoan Fa'afafine: A Retrospective Study.},
journal = {Archives of sexual behavior},
volume = {46},
number = {1},
pages = {95-108},
doi = {10.1007/s10508-016-0884-2},
pmid = {27987088},
issn = {1573-2800},
mesh = {Adult ; *Altruism ; Female ; Gender Identity ; Homosexuality, Male/*ethnology ; Humans ; Male ; Reproduction ; Retrospective Studies ; Samoa ; Sexual Behavior/*ethnology ; Siblings ; },
abstract = {Androphilia refers to sexual attraction toward adult males, whereas gynephilia refers to sexual attraction toward adult females. The kin selection hypothesis posits that androphilic males help kin increase their reproductive output via kin-directed altruism, thus offsetting their own lowered reproduction and contributing to the fitness of genes underpinning male androphilia. Support for this hypothesis has been garnered in several Samoan studies showing that feminine androphilic males (known locally as fa'afafine) report elevated willingness to invest in nieces and nephews in adulthood. Also, recalled childhood kin attachment and concern for kin's well-being are elevated among Canadian androphilic males (i.e., gay men) and positively associated with childhood feminine gender expression. This study examined whether these childhood patterns were cross-culturally consistent and associated with adulthood kin-directed altruism in a Samoan sample. Samoan gynephilic men, androphilic women, and fa'afafine (N = 470) completed measures of recalled childhood kin attachment and concern for the well-being of kin, recalled childhood gender expression, and willingness in adulthood to invest in nieces and nephews. Fa'afafine recalled elevated anxiety due to separation from kin relative to men and elevated concern for kin's well-being relative to both men and women. Within groups, these characteristics were most robustly associated with childhood feminine gender expression and willingness in adulthood to invest in nieces and nephews among fa'afafine. These findings are consistent with the kin selection hypothesis and the adaptive feminine phenotype model, which proposes that a disposition toward elevated kin-directed altruism among androphilic males is associated with feminine gender expression.},
}
@article {pmid27951454,
year = {2017},
author = {Allen-Hermanson, S},
title = {Kamikazes and cultural evolution.},
journal = {Studies in history and philosophy of biological and biomedical sciences},
volume = {61},
number = {},
pages = {11-19},
doi = {10.1016/j.shpsc.2016.12.001},
pmid = {27951454},
issn = {1879-2499},
mesh = {*Altruism ; Biological Evolution ; *Cultural Evolution ; Humans ; Japan ; Selection, Genetic ; *Warfare ; },
abstract = {Is cultural evolution needed to explain altruistic selfsacrifice? Some contend that cultural traits (e.g. beliefs, behaviors, and for some "memes") replicate according to selection processes that have "floated free" from biology. One test case is the example of suicide kamikaze attacks in wartime Japan. Standard biological mechanisms-such as reciprocal altruism and kin selection-might not seem to apply here: The suicide pilots did not act on the expectation that others would reciprocate, and they were supposedly sacrificing themselves for country and emperor, not close relatives. Yet an examination of both the historical record and the demands of evolutionary theory suggest the kamikaze phenomenon does not cry out for explanation in terms of a special non-biological selection process. This weakens the case for cultural evolution, and has interesting implications for our understanding of altruistic self-sacrifice.},
}
@article {pmid27925168,
year = {2017},
author = {Tan, CK and Doyle, P and Bagshaw, E and Richardson, DS and Wigby, S and Pizzari, T},
title = {The contrasting role of male relatedness in different mechanisms of sexual selection in red junglefowl.},
journal = {Evolution; international journal of organic evolution},
volume = {71},
number = {2},
pages = {403-420},
doi = {10.1111/evo.13145},
pmid = {27925168},
issn = {1558-5646},
support = {BB/K014544/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; },
mesh = {Animals ; Chickens/genetics/*physiology ; Competitive Behavior ; Copulation ; Female ; Male ; *Mating Preference, Animal ; Spermatozoa/*physiology ; },
abstract = {In structured populations, competition for reproductive opportunities should be relaxed among related males. The few tests of this prediction often neglect the fact that sexual selection acts through multiple mechanisms, both before and after mating. We performed experiments to study the role of within-group male relatedness across pre- and postcopulatory mechanisms of sexual selection in social groups of red junglefowl, Gallus gallus, in which two related males and one unrelated male competed over females unrelated to all the males. We confirm theoretical expectations that, after controlling for male social status, competition over mating was reduced among related males. However, this effect was contrasted by other sexual selection mechanisms. First, females biased male mating in favor of the unrelated male, and might also favor his inseminations after mating. Second, males invested more-rather than fewer-sperm in postcopulatory competition with relatives. A number of factors may contribute to explain this counterintuitive pattern of sperm allocation, including trade-offs between male investment in pre- versus postcopulatory competition, differences in the relative relatedness of pre- versus postcopulatory competitors, and female bias in sperm utilization in response to male relatedness. Collectively, these results reveal that within-group male relatedness may have contrasting effects in different mechanisms of sexual selection.},
}
@article {pmid27910006,
year = {2016},
author = {Coco, E},
title = {William D. Hamilton's Brazilian lectures and his unpublished model regarding Wynne-Edwards's idea of natural selection. With a note on 'pluralism' and different philosophical approaches to evolution.},
journal = {History and philosophy of the life sciences},
volume = {38},
number = {4},
pages = {24},
doi = {10.1007/s40656-016-0125-y},
pmid = {27910006},
issn = {0391-9714},
mesh = {Animals ; *Biological Evolution ; Brazil ; England ; *Genetic Variation ; Genetics, Population/*history ; History, 20th Century ; Manuscripts as Topic ; *Selection, Genetic ; *Social Behavior ; },
abstract = {In 1975, the English evolutionist William Donald Hamilton (1936-2000) held in Brazil a series of lectures entitled "Population genetics and social behaviour". The unpublished notes of these conferences-written by Hamilton and recently discovered at the British Library-offer an opportunity to reflect on some of the author's ideas about evolution. The year of the conference is particularly significant, as it took place shortly after the applications of the Price equation with which Hamilton was able to build a model that included several levels of selection. In this paper I mainly analyse the inaugural lecture in which Hamilton proposes a simple model to disprove the hypothesis supported by the British zoologist C. Vero Wynne-Edwards (1906-1997) regarding mechanisms to prevent "over-exploitation of the food supply" in "the interests of the survival of the group". The document presented here is of great historical interest. Not only because manuscript offers a model that-since it was intended for teaching purposes-had never before appeared in the published version, but also because of the general index of the lectures that accompanies it. The latter allows us to make some hypothetical considerations on the relationship and differences between kin-selection, group-selection and inclusive fitness that Hamilton wanted to present to the attentive, well-prepared audience of the foreign university that had invited him.},
}
@article {pmid27881747,
year = {2016},
author = {Duthie, AB and Lee, AM and Reid, JM},
title = {Inbreeding parents should invest more resources in fewer offspring.},
journal = {Proceedings. Biological sciences},
volume = {283},
number = {1843},
pages = {},
doi = {10.1098/rspb.2016.1845},
pmid = {27881747},
issn = {1471-2954},
mesh = {Animals ; Female ; *Genetic Fitness ; *Inbreeding ; Male ; *Mating Preference, Animal ; Models, Genetic ; *Reproduction ; },
abstract = {Inbreeding increases parent-offspring relatedness and commonly reduces offspring viability, shaping selection on reproductive interactions involving relatives and associated parental investment (PI). Nevertheless, theories predicting selection for inbreeding versus inbreeding avoidance and selection for optimal PI have only been considered separately, precluding prediction of optimal PI and associated reproductive strategy given inbreeding. We unify inbreeding and PI theory, demonstrating that optimal PI increases when a female's inbreeding decreases the viability of her offspring. Inbreeding females should therefore produce fewer offspring due to the fundamental trade-off between offspring number and PI. Accordingly, selection for inbreeding versus inbreeding avoidance changes when females can adjust PI with the degree that they inbreed. By contrast, optimal PI does not depend on whether a focal female is herself inbred. However, inbreeding causes optimal PI to increase given strict monogamy and associated biparental investment compared with female-only investment. Our model implies that understanding evolutionary dynamics of inbreeding strategy, inbreeding depression, and PI requires joint consideration of the expression of each in relation to the other. Overall, we demonstrate that existing PI and inbreeding theories represent special cases of a more general theory, implying that intrinsic links between inbreeding and PI affect evolution of behaviour and intrafamilial conflict.},
}
@article {pmid27859791,
year = {2016},
author = {Schultner, E and Saramäki, J and Helanterä, H},
title = {Genetic structure of native ant supercolonies varies in space and time.},
journal = {Molecular ecology},
volume = {25},
number = {24},
pages = {6196-6213},
doi = {10.1111/mec.13912},
pmid = {27859791},
issn = {1365-294X},
mesh = {Animals ; Ants/*genetics ; Finland ; *Genetics, Population ; Social Behavior ; Spatio-Temporal Analysis ; },
abstract = {Ant supercolonies are the largest cooperative units known in nature. They consist of networks of interconnected nests with hundreds of reproductive queens, where individuals move freely between nests, cooperate across nest boundaries and show little aggression towards non-nestmates. The combination of high queen numbers and free mixing of workers, queens and brood between nests results in extremely low nestmate relatedness. In such low-relatedness societies, cooperative worker behaviour appears maladaptive because it may aid random individuals instead of relatives. Here, we provide a comprehensive picture of genetic substructure in supercolonies of the native wood ant Formica aquilonia using traditional population genetic as well as network analysis methods. Specifically, we test for spatial and temporal variation in genetic structure of different classes of individuals within supercolonies and analyse the role of worker movement in determining supercolony genetic networks. We find that relatedness within supercolonies is low but positive when viewed on a population level, which may be due to limited dispersal of individuals and/or ecological factors such as nest site limitation and competition against conspecifics. Genetic structure of supercolonies varied with both sample class and sampling time point, which indicates that mobility of individuals varies according to both caste and season and suggests that generalizing has to be carried out with caution in studies of supercolonial species. Overall, our analysis provides novel evidence that native wood ant supercolonies exhibit fine-scale genetic substructure, which may explain the maintenance of cooperation in these low-relatedness societies.},
}
@article {pmid27852800,
year = {2016},
author = {Bawa, KS},
title = {Kin selection and the evolution of plant reproductive traits.},
journal = {Proceedings. Biological sciences},
volume = {283},
number = {1842},
pages = {},
doi = {10.1098/rspb.2016.0789},
pmid = {27852800},
issn = {1471-2954},
mesh = {*Biological Evolution ; Flowers/genetics ; Phenotype ; *Plant Physiological Phenomena ; Plants/*genetics ; Pollen/genetics ; *Pollination ; Reproduction ; Seeds/*genetics ; },
abstract = {Competition among developing seeds and sibling rivalry within multiovulated ovaries can be deleterious for both the maternal parent and the siblings. Increased genetic relatedness of seeds within the ovary may foster kin selection and reduce the deleterious consequences of sibling competition. The pollen parent may also be selected for siring all progeny within a fruit. I propose a series of hypotheses to explain the evolution of a number of reproductive traits in angiosperms in the context of kin selection and sibling rivalry within the ovaries of angiosperms. I present evidence to show that a single-pollen parent, indeed, often sires seeds within multiovulated ovaries. Various types of pollen aggregations and transfer of such pollen masses to the stigmas of flowers by specialized pollinators make this increased genetic relatedness possible. An alternative mode to reduce sibling rivalry may be the reduction of ovule number to one, an evolutionary trend that has independently occurred many times in flowering plants. Finally, I build on previously established correlations to predict two sets of correlations among reproductive traits. In the first case, large showy flowers, transfer of pollen en masse by specialized pollinators, and multiovulated ovaries and multisided fruits seem to be correlated. In the second case, the previously established correlations among small and inconspicuous flowers, pollination by wind, water or generalist insects, flowers and fruits with few or single ovules and seeds, respectively, may also include monoecy or dioecy. Although correlations among many of these traits have been established in the past, I invoke kin selection and sibling competition to explain the evolution of correlated traits as two distinct evolutionary pathways in angiosperms.},
}
@article {pmid27812427,
year = {2016},
author = {Saberski, ET and Diamond, JD and Henneman, NF and Levitis, DA},
title = {Post-reproductive parthenogenetic pea aphids (Acyrthosiphon pisum) are visually identifiable and disproportionately positioned distally to clonal colonies.},
journal = {PeerJ},
volume = {4},
number = {},
pages = {e2631},
doi = {10.7717/peerj.2631},
pmid = {27812427},
issn = {2167-8359},
abstract = {The role of kin-selection in the evolution of post-reproductive life is controversial. While anthropological and demographic studies strongly suggest that humans and a few other species experience kin selection for significant post-reproductive survival, these results are necessarily correlational. Understanding could therefore be advanced by the development of a globally available, field and laboratory tractable experimental model of kin-selected post-reproductive survival. In only one invertebrate (Quadrartus yoshinomiyai, a gall-forming aphid endemic to Japan) have individuals too old to reproduce been shown to be both numerous in natural habitats and able to help close relatives survive or reproduce. Pea aphids, (Acyrthosiphon pisum), common, tractable organisms, frequently outlive their reproductive ages in laboratories, live in tight interacting groups that are often clonal, and therefore should be evaluated as potential model organisms for the study of adaptive post-reproductive life. The first major step in this process is to identify an optimal method for assessing if a parthenogenetic adult is post-reproductive. We evaluated three methods, relying respectively on isolation in clip cages, visual examination for embryonic eyespots, and dissection. In every case each method identified the same individuals as reproductive versus post-reproductive. While the clip-cage method requires a multi-day wait to produce data, and dissection is inevitably fatal, the eyespot method is quick (under one minute per individual) easy, and non-invasive. This method makes it possible to accurately assess the post-reproductive status of a large number of parthenogenetic pea aphids. We demonstrate the usefulness of the eyespot method in showing that while reproductively valuable adults tend to place themselves near the centers of clonal colonies, less valuable post-reproductive adults are more often at or beyond the edges of colonies. These encouraging early results provide both impetuous and aid for further investigations into the post-reproductive lives of pea aphids.},
}
@article {pmid27798295,
year = {2016},
author = {Lion, S and Gandon, S},
title = {Spatial evolutionary epidemiology of spreading epidemics.},
journal = {Proceedings. Biological sciences},
volume = {283},
number = {1841},
pages = {},
doi = {10.1098/rspb.2016.1170},
pmid = {27798295},
issn = {1471-2954},
mesh = {Animals ; *Biological Evolution ; Epidemics ; *Host-Parasite Interactions ; *Models, Biological ; Parasites ; Parasitic Diseases/*epidemiology ; Spatial Analysis ; Virulence ; },
abstract = {Most spatial models of host-parasite interactions either neglect the possibility of pathogen evolution or consider that this process is slow enough for epidemiological dynamics to reach an equilibrium on a fast timescale. Here, we propose a novel approach to jointly model the epidemiological and evolutionary dynamics of spatially structured host and pathogen populations. Starting from a multi-strain epidemiological model, we use a combination of spatial moment equations and quantitative genetics to analyse the dynamics of mean transmission and virulence in the population. A key insight of our approach is that, even in the absence of long-term evolutionary consequences, spatial structure can affect the short-term evolution of pathogens because of the build-up of spatial differentiation in mean virulence. We show that spatial differentiation is driven by a balance between epidemiological and genetic effects, and this quantity is related to the effect of kin competition discussed in previous studies of parasite evolution in spatially structured host populations. Our analysis can be used to understand and predict the transient evolutionary dynamics of pathogens and the emergence of spatial patterns of phenotypic variation.},
}
@article {pmid27786267,
year = {2016},
author = {Camiletti, AL and Percival-Smith, A and Croft, JR and Thompson, GJ},
title = {A novel screen for genes associated with pheromone-induced sterility.},
journal = {Scientific reports},
volume = {6},
number = {},
pages = {36041},
doi = {10.1038/srep36041},
pmid = {27786267},
issn = {2045-2322},
mesh = {Animals ; Drosophila/*genetics/*physiology ; Fertility ; *Genes, Insect ; Genetic Testing/*methods ; Infertility ; Pheromones/*metabolism ; Sexual Behavior, Animal ; Smell ; },
abstract = {For honey bee and other social insect colonies the 'queen substance' regulates colony reproduction rendering workers functionally sterile. The evolution of worker reproductive altruism is explained by inclusive fitness theory, but little is known of the genes involved or how they regulate the phenotypic expression of altruism. We previously showed that application of honeybee queen pheromone to virgin fruit flies suppresses fecundity. Here we exploit this finding to identify genes associated with the perception of an ovary-inhibiting social pheromone. Mutational and RNAi approaches in Drosophila reveal that the olfactory co-factor Orco together with receptors Or49b, Or56a and Or98a are potentially involved in the perception of queen pheromone and the suppression of fecundity. One of these, Or98a, is known to mediate female fly mating behaviour, and its predicted ligand is structurally similar to a methyl component of the queen pheromone. Our novel approach to finding genes associated with pheromone-induced sterility implies conserved reproductive regulation between social and pre-social orders, and further helps to identify candidate orthologues from the pheromone-responsive pathway that may regulate honeybee worker sterility.},
}
@article {pmid27775099,
year = {2016},
author = {Zhang, BY and Fan, SJ and Li, C and Zheng, XD and Bao, JZ and Cressman, R and Tao, Y},
title = {Opting out against defection leads to stable coexistence with cooperation.},
journal = {Scientific reports},
volume = {6},
number = {},
pages = {35902},
doi = {10.1038/srep35902},
pmid = {27775099},
issn = {2045-2322},
abstract = {Cooperation coexisting with defection is a common phenomenon in nature and human society. Previous studies for promoting cooperation based on kin selection, direct and indirect reciprocity, graph selection and group selection have provided conditions that cooperators outcompete defectors. However, a simple mechanism of the long-term stable coexistence of cooperation and defection is still lacking. To reveal the effect of direct reciprocity on the coexistence of cooperation and defection, we conducted a simple experiment based on the Prisoner's Dilemma (PD) game, where the basic idea behind our experiment is that all players in a PD game should prefer a cooperator as an opponent. Our experimental and theoretical results show clearly that the strategies allowing opting out against defection are able to maintain this stable coexistence.},
}
@article {pmid27723824,
year = {2016},
author = {Beck, CM and Willett, JL and Cunningham, DA and Kim, JJ and Low, DA and Hayes, CS},
title = {CdiA Effectors from Uropathogenic Escherichia coli Use Heterotrimeric Osmoporins as Receptors to Recognize Target Bacteria.},
journal = {PLoS pathogens},
volume = {12},
number = {10},
pages = {e1005925},
doi = {10.1371/journal.ppat.1005925},
pmid = {27723824},
issn = {1553-7374},
support = {R01 GM117930/GM/NIGMS NIH HHS/United States ; },
mesh = {Contact Inhibition/physiology ; Escherichia coli Proteins/*metabolism ; Flow Cytometry ; Immunoblotting ; Membrane Proteins/*metabolism ; Porins/*metabolism ; Uropathogenic Escherichia coli/*metabolism ; },
abstract = {Many Gram-negative bacterial pathogens express contact-dependent growth inhibition (CDI) systems that promote cell-cell interaction. CDI+ bacteria express surface CdiA effector proteins, which transfer their C-terminal toxin domains into susceptible target cells upon binding to specific receptors. CDI+ cells also produce immunity proteins that neutralize the toxin domains delivered from neighboring siblings. Here, we show that CdiAEC536 from uropathogenic Escherichia coli 536 (EC536) uses OmpC and OmpF as receptors to recognize target bacteria. E. coli mutants lacking either ompF or ompC are resistant to CDIEC536-mediated growth inhibition, and both porins are required for target-cell adhesion to inhibitors that express CdiAEC536. Experiments with single-chain OmpF fusions indicate that the CdiAEC536 receptor is heterotrimeric OmpC-OmpF. Because the OmpC and OmpF porins are under selective pressure from bacteriophages and host immune systems, their surface-exposed loops vary between E. coli isolates. OmpC polymorphism has a significant impact on CDIEC536 mediated competition, with many E. coli isolates expressing alleles that are not recognized by CdiAEC536. Analyses of recombinant OmpC chimeras suggest that extracellular loops L4 and L5 are important recognition epitopes for CdiAEC536. Loops L4 and L5 also account for much of the sequence variability between E. coli OmpC proteins, raising the possibility that CDI contributes to the selective pressure driving OmpC diversification. We find that the most efficient CdiAEC536 receptors are encoded by isolates that carry the same cdi gene cluster as E. coli 536. Thus, it appears that CdiA effectors often bind preferentially to "self" receptors, thereby promoting interactions between sibling cells. As a consequence, these effector proteins cannot recognize nor suppress the growth of many potential competitors. These findings suggest that self-recognition and kin selection are important functions of CDI.},
}
@article {pmid27720058,
year = {2016},
author = {Séguret, A and Bernadou, A and Paxton, RJ},
title = {Facultative social insects can provide insights into the reversal of the longevity/fecundity trade-off across the eusocial insects.},
journal = {Current opinion in insect science},
volume = {16},
number = {},
pages = {95-103},
doi = {10.1016/j.cois.2016.06.001},
pmid = {27720058},
issn = {2214-5753},
mesh = {Animals ; *Biological Evolution ; Insecta/*physiology ; Longevity/*physiology ; Reproduction/physiology ; Selection, Genetic ; Social Behavior ; },
abstract = {In eusocial insects, reversal of the fecundity/longevity trade-off and extreme differences in life histories between castes of the same species garner scientific and public interest. Facultative social species at the threshold of sociality, in which individuals are socially plastic, provide an excellent opportunity to understand the causes and mechanisms underlying this reversal in life history trade-off associated with eusociality. We briefly present the ultimate factors favoring sociality and the association between fecundity and longevity in facultative eusocial insects, including kin selection and disposable soma, as well as proximate mechanisms observed in such species, such as differences in hormone titers and functions. Potential genetic underpinnings of lifespan and fecundity differences between castes are discussed and future research directions are proposed.},
}
@article {pmid27656086,
year = {2016},
author = {Walker, LA and York, JE and Young, AJ},
title = {Sexually selected sentinels? Evidence of a role for intrasexual competition in sentinel behavior.},
journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology},
volume = {27},
number = {5},
pages = {1461-1470},
doi = {10.1093/beheco/arw064},
pmid = {27656086},
issn = {1045-2249},
support = {BB/H022716/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; },
abstract = {Although the evolutionary mechanisms that favor investment in cooperative behaviors have long been a focus of research, comparatively few studies have considered the role that sexual selection may play. For example, evolutionary explanations for sentinel behavior (where 1 individual assumes an elevated position and scans the surroundings while other group members forage nearby) have traditionally focused on the inclusive fitness benefits arising from its effects on predation risk, while its potential role in defense against intrasexual competitors remains largely unexplored. Here, we provide experimental evidence of a role for sentinel behavior in intrasexual competition, in a cooperatively breeding songbird, the white-browed sparrow weaver (Plocepasser mahali). First, dominant males sentinel substantially more than other group members (even when controlling for variation in age and body condition), consistent with a role for sentineling in intrasexual competition for mates and/or territory. Second, experimental playback of an unfamiliar male's solo song elicited a marked increase in sentineling by the dominant male, and the vocal response to the playback also positively predicted his sentinel effort following the simulated intrusion. A second experiment also suggests that sentineling may facilitate mounting rapid anti-intruder responses, as responses to intruder-playback occurred significantly earlier when the dominant male was sentineling rather than foraging at playback onset. Together, our findings provide rare support for the hypothesis that sentinel behavior plays a role in intrasexual competition, and so highlight the potential for sexually selected direct benefits to shape its expression in this and other social vertebrates.},
}
@article {pmid27656085,
year = {2016},
author = {He, QQ and Wu, JJ and Ji, T and Tao, Y and Mace, R},
title = {Not leaving home: grandmothers and male dispersal in a duolocal human society.},
journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology},
volume = {27},
number = {5},
pages = {1343-1352},
doi = {10.1093/beheco/arw053},
pmid = {27656085},
issn = {1045-2249},
abstract = {Models suggest that dispersal patterns will influence age- and sex-dependent helping behavior in social species. Duolocal social systems (where neither sex disperses and mating is outside the group) are predicted to be associated with mothers favoring sons over daughters (because the latter are in reproductive competition with each other). Other models predict daughter-biased investment when benefits of wealth to sons are less than daughters. Here, we test whether sex-biased investment is occurring in the duolocal Mosuo of southwestern China. Using demographic and observational data from Mosuo, we show support for both hypotheses, in that 1) males are more likely to disperse from their natal household if their mother dies, but females are not; 2) a large number of brothers increases the likelihood that both females and males disperse, whereas a large number of sisters only increases female dispersal; 3) mothers help daughters reproduce earlier and reduce death risk of daughter's children, but not sons or sons' children; 4) data on multiple paternity show that female reproductive success does not suffer from multiple partners, and in males multiple mates are associated with higher reproductive success, indicating that mothers can benefit from investing in their sons' mating effort; and 5) gift decisions reveal similar kin effects to those shown in the demographic data, with mothers helping adult daughters and adult sons equally, but helping only her daughter's children, not her son's children. Mosuo mothers may invest resources for parental investment in their daughters and their offspring, while investing in their sons mating effort.},
}
@article {pmid27648229,
year = {2016},
author = {Städele, V and Vigilant, L},
title = {Strategies for determining kinship in wild populations using genetic data.},
journal = {Ecology and evolution},
volume = {6},
number = {17},
pages = {6107-6120},
doi = {10.1002/ece3.2346},
pmid = {27648229},
issn = {2045-7758},
abstract = {Knowledge of kin relationships between members of wild animal populations has broad application in ecology and evolution research by allowing the investigation of dispersal dynamics, mating systems, inbreeding avoidance, kin recognition, and kin selection as well as aiding the management of endangered populations. However, the assessment of kinship among members of wild animal populations is difficult in the absence of detailed multigenerational pedigrees. Here, we first review the distinction between genetic relatedness and kinship derived from pedigrees and how this makes the identification of kin using genetic data inherently challenging. We then describe useful approaches to kinship classification, such as parentage analysis and sibship reconstruction, and explain how the combined use of marker systems with biparental and uniparental inheritance, demographic information, likelihood analyses, relatedness coefficients, and estimation of misclassification rates can yield reliable classifications of kinship in groups with complex kin structures. We outline alternative approaches for cases in which explicit knowledge of dyadic kinship is not necessary, but indirect inferences about kinship on a group- or population-wide scale suffice, such as whether more highly related dyads are in closer spatial proximity. Although analysis of highly variable microsatellite loci is still the dominant approach for studies on wild populations, we describe how the long-awaited use of large-scale single-nucleotide polymorphism and sequencing data derived from noninvasive low-quality samples may eventually lead to highly accurate assessments of varying degrees of kinship in wild populations.},
}
@article {pmid27600591,
year = {2017},
author = {Lahvis, GP},
title = {Social Reward and Empathy as Proximal Contributions to Altruism: The Camaraderie Effect.},
journal = {Current topics in behavioral neurosciences},
volume = {30},
number = {},
pages = {127-157},
doi = {10.1007/7854_2016_449},
pmid = {27600591},
issn = {1866-3370},
support = {R01 DA022543/DA/NIDA NIH HHS/United States ; },
mesh = {*Altruism ; Animals ; Empathy/physiology ; Humans ; Motivation/physiology ; *Reward ; Rodentia ; },
abstract = {Natural selection favors individuals to act in their own interests, implying that wild animals experience a competitive psychology. Animals in the wild also express helping behaviors, presumably at their own expense and suggestive of a more compassionate psychology. This apparent paradox can be partially explained by ultimate mechanisms that include kin selection, reciprocity, and multilevel selection, yet some theorists argue such ultimate explanations may not be sufficient and that an additional "stake in others" is necessary for altruism's evolution. We suggest this stake is the "camaraderie effect," a by-product of two highly adaptive psychological experiences: social motivation and empathy. Rodents can derive pleasure from access to others and this appetite for social rewards motivates individuals to live together, a valuable psychology when group living is adaptive. Rodents can also experience empathy, the generation of an affective state more appropriate to the situation of another compared to one's own. Empathy is not a compassionate feeling but it has useful predictive value. For instance, empathy allows an individual to feel an unperceived danger from social cues. Empathy of another's stance toward one's self would predict either social acceptance or ostracism and amplify one's physiological sensitivity to social isolation, including impaired immune responses and delayed wound healing. By contrast, altruistic behaviors would promote well-being in others and feelings of camaraderie from others, thereby improving one's own physiological well-being. Together, these affective states engender a stake in others necessary for the expression of altruistic behavior.},
}
@article {pmid27590987,
year = {2016},
author = {Lehtonen, J},
title = {Multilevel Selection in Kin Selection Language.},
journal = {Trends in ecology & evolution},
volume = {31},
number = {10},
pages = {752-762},
doi = {10.1016/j.tree.2016.07.006},
pmid = {27590987},
issn = {1872-8383},
mesh = {Animals ; *Biological Evolution ; *Selection, Genetic ; Social Behavior ; },
abstract = {Few issues have raised more debate among evolutionary biologists than kin selection (KS) versus multilevel selection (MLS). They are formally equivalent, but use different-looking mathematical approaches, and are not causally equivalent: for a given problem KS can be a more suitable causal explanation than MLS, and vice versa. Methods for analyzing a given model from both viewpoints would therefore be valuable. I argue that there is often an easy way to achieve this: MLS can be written using the components of KS. This applies to the very general regression approach as well as to the practical evolutionarily stable strategy (ESS) maximization approach, and can hence be used to analyze many common ESS models from a multilevel perspective. I demonstrate this with example models of gamete competition and limitation.},
}
@article {pmid27588754,
year = {2016},
author = {Jacob, G and Prévot, AC and Baudry, E},
title = {Feral Pigeons (Columba livia) Prefer Genetically Similar Mates despite Inbreeding Depression.},
journal = {PloS one},
volume = {11},
number = {9},
pages = {e0162451},
doi = {10.1371/journal.pone.0162451},
pmid = {27588754},
issn = {1932-6203},
mesh = {Animals ; Columbidae/*physiology ; Female ; *Inbreeding Depression ; Male ; Mating Preference, Animal/*physiology ; Reproduction/*physiology ; Sexual Behavior, Animal/physiology ; },
abstract = {Avoidance of mating between related individuals is usually considered adaptive because it decreases the probability of inbreeding depression in offspring. However, mating between related partners can be adaptive if outbreeding depression is stronger than inbreeding depression or if females gain inclusive fitness benefits by mating with close kin. In the present study, we used microsatellite data to infer the parentage of juveniles born in a French colony of feral pigeons, which allowed us to deduce parent pairs. Despite detectable inbreeding depression, we found that pairwise relatedness between mates was significantly higher than between nonmates, with a mean coefficient of relatedness between mates of 0.065, approximately half the theoretical value for first cousins. This higher relatedness between mates cannot be explained by spatial genetic structure in this colonial bird; it therefore probably results from an active choice. As inbreeding but not outbreeding depression is observed in the study population, this finding accords with the idea that mating with genetically similar mates can confer a benefit in terms of inclusive fitness. Our results and published evidence suggest that preference for related individuals as mates might be relatively frequent in birds.},
}
@article {pmid27579491,
year = {2016},
author = {Pfefferle, D and Hammerschmidt, K and Mundry, R and Ruiz-Lambides, AV and Fischer, J and Widdig, A},
title = {Does the Structure of Female Rhesus Macaque Coo Calls Reflect Relatedness and/or Familiarity?.},
journal = {PloS one},
volume = {11},
number = {8},
pages = {e0161133},
doi = {10.1371/journal.pone.0161133},
pmid = {27579491},
issn = {1932-6203},
support = {P40 OD012217/OD/NIH HHS/United States ; },
mesh = {Animals ; Female ; Macaca mulatta ; Vocalization, Animal/*physiology ; },
abstract = {In social animals, kin relations strongly shape the social structure of a group. In female-bonded species, maternal relatedness is likely to be mediated via familiarity, but evidence is accumulating that non-human primates are able to recognize kin that they are not familiar with and adjust their behavior accordingly. In playback experiments, female rhesus macaques showed increased interest in 'coo' calls produced by unfamiliar paternal half-sisters compared to 'coo' calls produced by unfamiliar unrelated females, suggesting that these calls should have some common structural characteristics that facilitate the discrimination of kin from non-kin. Here we analyzed 'coo' calls of 67 adult female rhesus macaques from four groups and seven matrilines living on the island of Cayo Santiago (Puerto Rico). We tested whether the call structure of closely maternal and/or paternal related females, as determined from extensive pedigree data, differed from the call structure of unrelated females, while controlling for familiarity (i.e., group-matrilineal membership and age difference) of subjects. In contrast to our expectation, kinship did not predict similarities in 'coo' call structure, whereas 'coo' structure was more similar when produced by females of similar age as well as by females with higher familiarity, suggesting that experience is more decisive than genetic background. The high number of individuals in the analysis and the high accuracy of the assignment of calls to individuals render a lack of power as an unlikely explanation. Thus, based on the results of this study, kin recognition in rhesus monkeys does neither appear to be based on the assessment of self-similarity, nor on the comparison among related subjects (i.e., acoustic phenotype matching), but appears to be mediated by different or multiple cues. Furthermore, the results support the notion that frequent social interactions result in increasing acoustic similarity within largely innate call types ('vocal accommodation').},
}
@article {pmid27576465,
year = {2016},
author = {Weiß, BM and Kulik, L and Ruiz-Lambides, AV and Widdig, A},
title = {Individual dispersal decisions affect fitness via maternal rank effects in male rhesus macaques.},
journal = {Scientific reports},
volume = {6},
number = {},
pages = {32212},
doi = {10.1038/srep32212},
pmid = {27576465},
issn = {2045-2322},
support = {P40 OD012217/OD/NIH HHS/United States ; },
mesh = {Animal Migration ; Animals ; Female ; Genetic Fitness ; Macaca mulatta/*physiology ; Male ; Reproduction ; Sex Ratio ; Sexual Behavior, Animal ; Social Behavior ; Social Dominance ; },
abstract = {Natal dispersal may have considerable social, ecological and evolutionary consequences. While species-specific dispersal strategies have received much attention, individual variation in dispersal decisions and its fitness consequences remain poorly understood. We investigated causes and consequences of natal dispersal age in rhesus macaques (Macaca mulatta), a species with male dispersal. Using long-term demographic and genetic data from a semi-free ranging population on Cayo Santiago, Puerto Rico, we analysed how the social environment such as maternal family, group and population characteristics affected the age at which males leave their natal group. While natal dispersal age was unrelated to most measures of group or population structure, our study confirmed earlier findings that sons of high-ranking mothers dispersed later than sons of low-ranking ones. Natal dispersal age did not affect males' subsequent survival, but males dispersing later were more likely to reproduce. Late dispersers were likely to start reproducing while still residing in their natal group, frequently produced extra-group offspring before natal dispersal and subsequently dispersed to the group in which they had fathered offspring more likely than expected. Hence, the timing of natal dispersal was affected by maternal rank and influenced male reproduction, which, in turn affected which group males dispersed to.},
}
@article {pmid27569292,
year = {2017},
author = {van Veelen, M and Allen, B and Hoffman, M and Simon, B and Veller, C},
title = {Hamilton's rule.},
journal = {Journal of theoretical biology},
volume = {414},
number = {},
pages = {176-230},
doi = {10.1016/j.jtbi.2016.08.019},
pmid = {27569292},
issn = {1095-8541},
mesh = {Animals ; *Biological Evolution ; Humans ; *Models, Biological ; Selection, Genetic/*physiology ; },
abstract = {This paper reviews and addresses a variety of issues relating to inclusive fitness. The main question is: are there limits to the generality of inclusive fitness, and if so, what are the perimeters of the domain within which inclusive fitness works? This question is addressed using two well-known tools from evolutionary theory: the replicator dynamics, and adaptive dynamics. Both are combined with population structure. How generally Hamilton's rule applies depends on how costs and benefits are defined. We therefore consider costs and benefits following from Karlin and Matessi's (1983) "counterfactual method", and costs and benefits as defined by the "regression method" (Gardner et al., 2011). With the latter definition of costs and benefits, Hamilton's rule always indicates the direction of selection correctly, and with the former it does not. How these two definitions can meaningfully be interpreted is also discussed. We also consider cases where the qualitative claim that relatedness fosters cooperation holds, even if Hamilton's rule as a quantitative prediction does not. We furthermore find out what the relation is between Hamilton's rule and Fisher's Fundamental Theorem of Natural Selection. We also consider cancellation effects - which is the most important deepening of our understanding of when altruism is selected for. Finally we also explore the remarkable (im)possibilities for empirical testing with either definition of costs and benefits in Hamilton's rule.},
}
@article {pmid27561630,
year = {2016},
author = {Nesse, RM},
title = {Social selection is a powerful explanation for prosociality.},
journal = {The Behavioral and brain sciences},
volume = {39},
number = {},
pages = {e47},
doi = {10.1017/S0140525X15000308},
pmid = {27561630},
issn = {1469-1825},
mesh = {Biological Evolution ; Humans ; *Interpersonal Relations ; Phenotype ; Reproduction ; Selection, Genetic ; *Social Behavior ; },
abstract = {Cultural group selection helps explain human cooperation, but social selection offers a complementary, more powerful explanation. Just as sexual selection shapes extreme traits that increase matings, social selection shapes extreme traits that make individuals preferred social partners. Self-interested partner choices create strong and possibly runaway selection for prosocial traits, without requiring group selection, kin selection, or reciprocity.},
}
@article {pmid27554604,
year = {2016},
author = {Green, JP and Freckleton, RP and Hatchwell, BJ},
title = {Variation in helper effort among cooperatively breeding bird species is consistent with Hamilton's Rule.},
journal = {Nature communications},
volume = {7},
number = {},
pages = {12663},
doi = {10.1038/ncomms12663},
pmid = {27554604},
issn = {2041-1723},
mesh = {Animals ; *Behavior, Animal ; Biological Evolution ; Birds/*physiology ; Breeding ; Cooperative Behavior ; Ecosystem ; Female ; Helping Behavior ; Male ; Models, Biological ; Phylogeny ; Sex Ratio ; Social Behavior ; Species Specificity ; },
abstract = {Investment by helpers in cooperative breeding systems is extremely variable among species, but this variation is currently unexplained. Inclusive fitness theory predicts that, all else being equal, cooperative investment should correlate positively with the relatedness of helpers to the recipients of their care. We test this prediction in a comparative analysis of helper investment in 36 cooperatively breeding bird species. We show that species-specific helper contributions to cooperative brood care increase as the mean relatedness between helpers and recipients increases. Helper contributions are also related to the sex ratio of helpers, but neither group size nor the proportion of nests with helpers influence helper effort. Our findings support the hypothesis that variation in helping behaviour among cooperatively breeding birds is consistent with Hamilton's rule, indicating a key role for kin selection in the evolution of cooperative investment in social birds.},
}
@article {pmid27534524,
year = {2016},
author = {Kowald, A and Kirkwood, TBL},
title = {Can aging be programmed? A critical literature review.},
journal = {Aging cell},
volume = {15},
number = {6},
pages = {986-998},
doi = {10.1111/acel.12510},
pmid = {27534524},
issn = {1474-9726},
abstract = {The evolution of the aging process has long been a biological riddle, because it is difficult to explain the evolution of a trait that has apparently no benefit to the individual. Over 60 years ago, Medawar realized that the force of natural selection declines with chronological age because of unavoidable environmental risks. This forms the basis of the mainstream view that aging arises as a consequence of a declining selection pressure to maintain the physiological functioning of living beings forever. Over recent years, however, a number of articles have appeared that nevertheless propose the existence of specific aging genes; that is, that the aging process is genetically programmed. If this view were correct, it would have serious implications for experiments to understand and postpone aging. Therefore, we studied in detail various specific proposals why aging should be programmed. We find that not a single one withstands close scrutiny of its assumptions or simulation results. Nonprogrammed aging theories based on the insight of Medawar (as further developed by Hamilton and Charlesworth) are still the best explanation for the evolution of the aging process. We hope that this analysis helps to clarify the problems associated with the idea of programmed aging.},
}
@article {pmid27485635,
year = {2016},
author = {Helanterä, H and Kulmuni, J and Pamilo, P},
title = {Sex allocation conflict between queens and workers in Formica pratensis wood ants predicts seasonal sex ratio variation.},
journal = {Evolution; international journal of organic evolution},
volume = {70},
number = {10},
pages = {2387-2394},
doi = {10.1111/evo.13018},
pmid = {27485635},
issn = {1558-5646},
mesh = {Animals ; Ants/*genetics/physiology ; Female ; Haploidy ; Male ; *Seasons ; *Sex Ratio ; },
abstract = {Sex allocation theory predicts parents should adjust their investment in male and female offspring in a way that increases parental fitness. This has been shown in several species and selective contexts. Yet, seasonal sex ratio variation within species and its underlying causes are poorly understood. Here, we study sex allocation variation in the wood ant Formica pratensis. This species displays conflict over colony sex ratio as workers and queens prefer different investment in male and female offspring, owing to haplodiploidy and relatedness asymmetries. It is unique among Formica ants because it produces two separate sexual offspring cohorts per season. We predict sex ratios to be closer to queen optimum in the early cohort but more female-biased and closer to worker optimum in the later one. This is because the power of workers to manipulate colony sex ratio varies seasonally with the availability of diploid eggs. Consistently, more female-biased sex ratios in the later offspring cohort over a three-year sampling period from 93 colonies clearly support our prediction. The resulting seasonal alternation of sex ratios between queen and worker optima is a novel demonstration how understanding constraints of sex ratio adjustment increases our ability to predict sex ratio variation.},
}
@article {pmid27483372,
year = {2016},
author = {Makowicz, AM and Tiedemann, R and Steele, RN and Schlupp, I},
title = {Kin Recognition in a Clonal Fish, Poecilia formosa.},
journal = {PloS one},
volume = {11},
number = {8},
pages = {e0158442},
doi = {10.1371/journal.pone.0158442},
pmid = {27483372},
issn = {1932-6203},
mesh = {Aggression ; Animals ; Behavior, Animal ; Female ; Genetic Variation ; Genetics, Population ; Male ; Microsatellite Repeats ; Poecilia/anatomy & histology/*genetics/physiology ; Selection, Genetic ; Social Behavior ; Texas ; },
abstract = {Relatedness strongly influences social behaviors in a wide variety of species. For most species, the highest typical degree of relatedness is between full siblings with 50% shared genes. However, this is poorly understood in species with unusually high relatedness between individuals: clonal organisms. Although there has been some investigation into clonal invertebrates and yeast, nothing is known about kin selection in clonal vertebrates. We show that a clonal fish, the Amazon molly (Poecilia formosa), can distinguish between different clonal lineages, associating with genetically identical, sister clones, and use multiple sensory modalities. Also, they scale their aggressive behaviors according to the relatedness to other females: they are more aggressive to non-related clones. Our results demonstrate that even in species with very small genetic differences between individuals, kin recognition can be adaptive. Their discriminatory abilities and regulation of costly behaviors provides a powerful example of natural selection in species with limited genetic diversity.},
}
@article {pmid27480245,
year = {2016},
author = {Jacob, S and Wehi, P and Clobert, J and Legrand, D and Schtickzelle, N and Huet, M and Chaine, A},
title = {Cooperation-mediated plasticity in dispersal and colonization.},
journal = {Evolution; international journal of organic evolution},
volume = {70},
number = {10},
pages = {2336-2345},
doi = {10.1111/evo.13028},
pmid = {27480245},
issn = {1558-5646},
mesh = {Biological Evolution ; Cell Aggregation/genetics ; Genotype ; *Models, Genetic ; Tetrahymena thermophila/*genetics/physiology ; },
abstract = {Kin selection theory predicts that costly cooperative behaviors evolve most readily when directed toward kin. Dispersal plays a controversial role in the evolution of cooperation: dispersal decreases local population relatedness and thus opposes the evolution of cooperation, but limited dispersal increases kin competition and can negate the benefits of cooperation. Theoretical work has suggested that plasticity of dispersal, where individuals can adjust their dispersal decisions according to the social context, might help resolve this paradox and promote the evolution of cooperation. Here, we experimentally tested the hypothesis that conditional dispersal decisions are mediated by a cooperative strategy: we quantified the density-dependent dispersal decisions and subsequent colonization efficiency from single cells or groups of cells among six genetic strains of the unicellular Tetrahymena thermophila that differ in their aggregation level (high, medium, and low), a behavior associated with cooperation strategy. We found that the plastic reaction norms of dispersal rate relative to density differed according to aggregation level: highly aggregative genotypes showed negative density-dependent dispersal, whereas low-aggregation genotypes showed maximum dispersal rates at intermediate density, and medium-aggregation genotypes showed density-independent dispersal with intermediate dispersal rate. Dispersers from highly aggregative genotypes had specialized long-distance dispersal phenotypes, contrary to low-aggregation genotypes; medium-aggregation genotypes showing intermediate dispersal phenotype. Moreover, highly aggregation genotypes showed evidence for beneficial kin-cooperation during dispersal. Our experimental results should help to resolve the evolutionary conflict between cooperation and dispersal: cooperative individuals are expected to avoid kin-competition by dispersing long distances, but maintain the benefits of cooperation by dispersing in small groups.},
}
@article {pmid27478299,
year = {2016},
author = {Kerhoas, D and Kulik, L and Perwitasari-Farajallah, D and Agil, M and Engelhardt, A and Widdig, A},
title = {Mother-male bond, but not paternity, influences male-infant affiliation in wild crested macaques.},
journal = {Behavioral ecology and sociobiology},
volume = {70},
number = {},
pages = {1117-1130},
doi = {10.1007/s00265-016-2116-0},
pmid = {27478299},
issn = {0340-5443},
abstract = {ABSTRACT: In promiscuous primates, interactions between adult males and infants have rarely been investigated. However, recent evidence suggests that male affiliation towards infants has an influence on several aspects of the infants' life. Furthermore, affiliations may be associated with male reproductive strategy. In this study, we examined which social factors influenced male-infant affiliation initiated by either male or infant, in wild crested macaques (Macaca nigra). We combined behavioral data and genetic paternity analysis from 30 infants living in three wild groups in Tangkoko Reserve, Indonesia. Our results indicate that adult males and infants do not interact at random, but rather form preferential associations. The social factors with the highest influence on infant-initiated interactions were male rank and male association with the infant's mother. While infants initiated affiliations with males more often in the absence of their mothers, adult males initiated more affiliations with infants when their mothers were present. Furthermore, males initiated affiliations more often when they were in the same group at the time the infant was conceived, when they held a high dominance rank, or when they had a close relationship with the mother. Interestingly, paternity did not affect male-infant affiliation despite being highly skewed in this species. Overall, our results suggest that adult males potentially associate with an infant to secure future mating with the mother. Infants are more likely to associate with a male to receive better support, suggesting a strategy to increase the chance of infant survival in a primate society with high infant mortality.

METHODS/DESIGN: Romanian-speaking adults (18 years or older) with elevated Beck Depression Inventory (BDI) scores (>13), current diagnosis of major depressive disorder or major depressive episode (MDD or MDE), and MDD with comorbid dysthymia, as evaluated by the Structured Clinical Interview for DSM-IV (SCID), are included in the study. Participants are randomized to one of two conditions: 1) evolutionary-driven cognitive therapy (ED-CT) or 2) cognitive therapy (CT). Both groups undergo 12 psychotherapy sessions, and data are collected at baseline, mid-treatment, post-treatment, and the 3-month follow-up. Primary outcomes are depressive symptomatology and a categorical diagnosis of depression post-treatment.

DISCUSSION: This randomized trial compares the newly proposed ED-CT with a classic CT protocol for depression. To our knowledge, this is the first attempt to integrate insights from evolutionary theories of depression into the treatment of this condition in a controlled manner. This study can thus add substantially to the body of knowledge on validated treatments for depression.

TRIAL REGISTRATION: Current Controlled Trials ISRCTN64664414The trial was registered in June 2013. The first participant was enrolled on October 3, 2012.},
}
@article {pmid24631046,
year = {2014},
author = {Wakano, JY and Lehmann, L},
title = {Evolutionary branching in deme-structured populations.},
journal = {Journal of theoretical biology},
volume = {351},
number = {},
pages = {83-95},
doi = {10.1016/j.jtbi.2014.02.036},
pmid = {24631046},
issn = {1095-8541},
mesh = {Algorithms ; Animals ; *Biological Evolution ; Game Theory ; Genetic Drift ; *Models, Genetic ; Mutation ; Population Density ; Population Dynamics ; Selection, Genetic ; },
abstract = {Adaptive dynamics shows that a continuous trait under frequency dependent selection may first converge to a singular point followed by spontaneous transition from a unimodal trait distribution into a bimodal one, which is called "evolutionary branching". Here, we study evolutionary branching in a deme-structured population by constructing a quantitative genetic model for the trait variance dynamics, which allows us to obtain an analytic condition for evolutionary branching. This is first shown to agree with previous conditions for branching expressed in terms of relatedness between interacting individuals within demes and obtained from mutant-resident systems. We then show this branching condition can be markedly simplified when the evolving trait affect fecundity and/or survival, as opposed to affecting population structure, which would occur in the case of the evolution of dispersal. As an application of our model, we evaluate the threshold migration rate below which evolutionary branching cannot occur in a pairwise interaction game. This agrees very well with the individual-based simulation results.},
}
@article {pmid24624128,
year = {2014},
author = {Bapteste, E},
title = {The origins of microbial adaptations: how introgressive descent, egalitarian evolutionary transitions and expanded kin selection shape the network of life.},
journal = {Frontiers in microbiology},
volume = {5},
number = {},
pages = {83},
doi = {10.3389/fmicb.2014.00083},
pmid = {24624128},
issn = {1664-302X},
}
@article {pmid24621140,
year = {2014},
author = {Bichet, C and Penn, DJ and Moodley, Y and Dunoyer, L and Cellier-Holzem, E and Belvalette, M and Grégoire, A and Garnier, S and Sorci, G},
title = {Females tend to prefer genetically similar mates in an island population of house sparrows.},
journal = {BMC evolutionary biology},
volume = {14},
number = {1},
pages = {47},
doi = {10.1186/1471-2148-14-47},
pmid = {24621140},
issn = {1471-2148},
mesh = {Animals ; Female ; France ; Genes, MHC Class I ; Genetic Variation ; Inbreeding ; Islands ; Male ; *Mating Preference, Animal ; Microsatellite Repeats ; Sparrows/*genetics/physiology ; },
abstract = {BACKGROUND: It is often proposed that females should select genetically dissimilar mates to maximize offspring genetic diversity and avoid inbreeding. Several recent studies have provided mixed evidence, however, and in some instances females seem to prefer genetically similar males. A preference for genetically similar mates can be adaptive if outbreeding depression is more harmful than inbreeding depression or if females gain inclusive fitness benefits by mating with close kin. Here, we investigated genetic compatibility and mating patterns in an insular population of house sparrow (Passer domesticus), over a three-year period, using 12 microsatellite markers and one major histocompability complex (MHC) class I gene. Given the small population size and the distance from the mainland, we expected a reduced gene flow in this insular population and we predicted that females would show mating preferences for genetically dissimilar mates.

RESULTS: Contrary to our expectation, we found that offspring were less genetically diverse (multi-locus heterozygosity) than expected under a random mating, suggesting that females tended to mate with genetically similar males. We found high levels of extra-pair paternity, and offspring sired by extra-pair males had a better fledging success than those sired by the social male. Again, unexpectedly, females tended to be more closely related to extra-pair mates than to their social mates. Our results did not depend on the type of genetic marker used, since microsatellites and MHC genes provided similar results, and we found only little evidence for MHC-dependent mating patterns.

CONCLUSIONS: These results are in agreement with the idea that mating with genetically similar mates can either avoid the disruption of co-adapted genes or confer a benefit in terms of kin selection.},
}
@article {pmid24619652,
year = {2014},
author = {VanderLaan, DP and Vasey, PL},
title = {Evidence of cognitive biases for maximizing indirect fitness in Samoan fa'afafine.},
journal = {Archives of sexual behavior},
volume = {43},
number = {5},
pages = {1009-1022},
doi = {10.1007/s10508-014-0288-0},
pmid = {24619652},
issn = {1573-2800},
mesh = {Adult ; *Altruism ; Cognition ; Family/psychology ; *Family Relations ; Female ; *Genetic Fitness ; Homosexuality, Male/*psychology ; Humans ; Male ; Sexual Behavior ; },
abstract = {The kin selection hypothesis posits that male androphilia (i.e., sexual attraction to males), although detrimental to reproduction (i.e., direct fitness), has persisted and evolved because androphilic males compensate by increasing their indirect fitness via increased investment in kin. In previous studies, Samoan androphilic males (known locally as fa'afafine) reported elevated avuncular (i.e., uncle-like) tendencies compared to Samoan gynephilic (i.e., sexually attracted to females) men. Their avuncular tendencies were also greater than the materteral (i.e., aunt-like) tendencies of androphilic women. The present study examined whether the avuncular cognition of fa'afafine was enhanced for maximizing indirect fitness. To do so, it examined whether fa'afafine had a stronger propensity than Samoan gynephilic men and androphilic women to invest in kin categories that would result in more reliable and substantive increases in indirect fitness (i.e., young, female kin) in hypothetical investment scenarios. In a forced-choice paradigm, although all individuals showed some degree of bias to invest in adaptive kin categories during non-frivolous investment contexts in which the consequences of investment were relatively non-trivial, fa'afafine showed greater adherence to the predicted pattern. In addition, shifting the context from frivolous investments, in which the consequences of investment were relatively trivial, to non-frivolous investments prompted fa'afafine to exhibit an enhanced preference, relative to Samoan gynephilic men and androphilic women, to invest in adaptive kin categories. These findings were consistent with the kin selection hypothesis and suggest that, although all individuals exhibit cognitive biases for increasing indirect fitness, the avuncular cognition of androphilic males has undergone selective enhancement to maximize the accrual of indirect fitness via kin-directed altruism.},
}
@article {pmid24601980,
year = {2014},
author = {Pradhan, BB and Chatterjee, S},
title = {Reversible non-genetic phenotypic heterogeneity in bacterial quorum sensing.},
journal = {Molecular microbiology},
volume = {92},
number = {3},
pages = {557-569},
doi = {10.1111/mmi.12575},
pmid = {24601980},
issn = {1365-2958},
mesh = {Acyl-Butyrolactones/metabolism ; Fatty Acids/metabolism ; Phenotype ; Pseudomonas syringae/drug effects/*physiology ; *Quorum Sensing ; Xanthomonas campestris/drug effects/*physiology ; },
abstract = {Bacteria co-ordinate their social behaviour in a density-dependent manner by production of diffusible signal molecules by a process known as quorum sensing (QS). It is generally assumed that in homogenous environments and at high cell density, QS synchronizes cells in the population to perform collective social tasks in unison which maximize the benefit at the inclusive fitness of individuals. However, evolutionary theory predicts that maintaining phenotypic heterogeneity in performing social tasks is advantageous as it can serve as a bet-hedging survival strategy. Using Pseudomonas syringae and Xanthomonas campestris as model organisms, which use two diverse classes of QS signals, we show that two distinct subpopulations of QS-responsive and non-responsive cells exist in the QS-activated population. Addition of excess exogenous QS signal does not significantly alter the distribution of QS-responsive and non-responsive cells in the population. We further show that progeny of cells derived from these subpopulations also exhibited heterogeneous distribution patterns similar to their respective parental strains. Overall, these results support the model that bacteria maintain QS-responsive and non-responsive subpopulations at high cell densities in a bet-hedging strategy to simultaneously perform functions that are both positively and negatively regulated by QS to improve their fitness in fluctuating environments.},
}
@article {pmid24573154,
year = {2014},
author = {Durand, PM and Choudhury, R and Rashidi, A and Michod, RE},
title = {Programmed death in a unicellular organism has species-specific fitness effects.},
journal = {Biology letters},
volume = {10},
number = {2},
pages = {20131088},
doi = {10.1098/rsbl.2013.1088},
pmid = {24573154},
issn = {1744-957X},
mesh = {*Apoptosis ; Chlamydomonas/genetics/growth & development/*physiology ; *Genetic Fitness ; Hot Temperature ; Species Specificity ; },
abstract = {Programmed cell death (PCD) is an ancient phenomenon and its origin and maintenance in unicellular life is unclear. We report that programmed death provides differential fitness effects that are species specific in the model organism Chlamydomonas reinhardtii. Remarkably, PCD in this organism not only benefits others of the same species, but also has an inhibitory effect on the growth of other species. These data reveal that the fitness effects of PCD can depend upon genetic relatedness.},
}
@article {pmid24567830,
year = {2013},
author = {Sato, Y and Egas, M and Sabelis, MW and Mochizuki, A},
title = {Male-male aggression peaks at intermediate relatedness in a social spider mite.},
journal = {Ecology and evolution},
volume = {3},
number = {8},
pages = {2661-2669},
doi = {10.1002/ece3.661},
pmid = {24567830},
issn = {2045-7758},
abstract = {Theory predicts that when individuals live in groups or colonies, male-male aggression peaks at intermediate levels of local average relatedness. Assuming that aggression is costly and directed toward nonrelatives and that competition for reproduction acts within the colony, benefits of aggressive behavior are maximized in colonies with a mix of related and unrelated competitors because aggression hurts nonkin often, thereby favoring reproduction of kin. This leads to a dome-shaped relation between male-male aggression and average relatedness. This prediction has been tested with bacteria in the laboratory, but not with organisms in the field. We study how male-male aggression varies with relatedness in the social spider mite Stigmaeopsis miscanthi. We sampled 25 populations across a wide geographic range between Taiwan and Japan, representing a gradient of high to low within-population relatedness. For each population the weaponry of males was measured as the length of the first pair of legs, and male-male aggression was tested by placing pairs of nonsibling males together and scoring the frequency of male death over a given period. As these two morphological and behavioral variables correlate strongly, they both reflect the intensity of male-male conflict. Our data on the social spider mite show that male-male aggression as well as weapon size strongly peak at intermediate, average relatedness, thereby confirming theoretical predictions. Inclusive fitness theory predicts that when individuals live in groups or colonies, aggression should peak at intermediate levels of average relatedness in the colony. Here, we study how male-male aggression varies with average relatedness in naturally occurring colonies of the social spider mite Stigmaeopsis miscanthi. In support of theory, male-male aggression and weapon size strongly peak at intermediate average relatedness.},
}
@article {pmid24555438,
year = {2014},
author = {Kessler, SE and Radespiel, U and Hasiniaina, AI and Leliveld, LM and Nash, LT and Zimmermann, E},
title = {Modeling the origins of mammalian sociality: moderate evidence for matrilineal signatures in mouse lemur vocalizations.},
journal = {Frontiers in zoology},
volume = {11},
number = {1},
pages = {14},
doi = {10.1186/1742-9994-11-14},
pmid = {24555438},
issn = {1742-9994},
abstract = {INTRODUCTION: Maternal kin selection is a driving force in the evolution of mammalian social complexity and it requires that kin are distinctive from nonkin. The transition from the ancestral state of asociality to the derived state of complex social groups is thought to have occurred via solitary foraging, in which individuals forage alone, but, unlike the asocial ancestors, maintain dispersed social networks via scent-marks and vocalizations. We hypothesize that matrilineal signatures in vocalizations were an important part of these networks. We used the solitary foraging gray mouse lemur (Microcebus murinus) as a model for ancestral solitary foragers and tested for matrilineal signatures in their calls, thus investigating whether such signatures are already present in solitary foragers and could have facilitated the kin selection thought to have driven the evolution of increased social complexity in mammals. Because agonism can be very costly, selection for matrilineal signatures in agonistic calls should help reduce agonism between unfamiliar matrilineal kin. We conducted this study on a well-studied population of wild mouse lemurs at Ankarafantsika National Park, Madagascar. We determined pairwise relatedness using seven microsatellite loci, matrilineal relatedness by sequencing the mitrochondrial D-loop, and sleeping group associations using radio-telemetry. We recorded agonistic calls during controlled social encounters and conducted a multi-parametric acoustic analysis to determine the spectral and temporal structure of the agonistic calls. We measured 10 calls for each of 16 females from six different matrilineal kin groups.

CONCLUSIONS: Mouse lemur agonistic calls are moderately distinctive by matriline. Because sleeping groups consisted of close maternal kin, both genetics and social learning may have generated these acoustic signatures. As mouse lemurs are models for solitary foragers, we recommend further studies testing whether the lemurs use these calls to recognize kin. This would enable further modeling of how kin recognition in ancestral species could have shaped the evolution of complex sociality.},
}
@article {pmid24530825,
year = {2014},
author = {Okasha, S and Weymark, JA and Bossert, W},
title = {Inclusive fitness maximization: An axiomatic approach.},
journal = {Journal of theoretical biology},
volume = {350},
number = {},
pages = {24-31},
doi = {10.1016/j.jtbi.2014.02.002},
pmid = {24530825},
issn = {1095-8541},
mesh = {*Genetic Fitness ; *Models, Genetic ; },
abstract = {Kin selection theorists argue that evolution in social contexts will lead organisms to behave as if maximizing their inclusive, as opposed to personal, fitness. The inclusive fitness concept allows biologists to treat organisms as akin to rational agents seeking to maximize a utility function. Here we develop this idea and place it on a firm footing by employing a standard decision-theoretic methodology. We show how the principle of inclusive fitness maximization and a related principle of quasi-inclusive fitness maximization can be derived from axioms on an individual׳s 'as if preferences' (binary choices) for the case in which phenotypic effects are additive. Our results help integrate evolutionary theory and rational choice theory, help draw out the behavioural implications of inclusive fitness maximization, and point to a possible way in which evolution could lead organisms to implement it.},
}
@article {pmid24504534,
year = {2014},
author = {Hesse, S and Thünken, T},
title = {Growth and social behavior in a cichlid fish are affected by social rearing environment and kinship.},
journal = {Die Naturwissenschaften},
volume = {101},
number = {4},
pages = {273-283},
doi = {10.1007/s00114-014-1154-6},
pmid = {24504534},
issn = {1432-1904},
mesh = {Animals ; Behavior, Animal/*physiology ; Cichlids/growth & development/*physiology ; *Social Behavior ; *Social Environment ; },
abstract = {Living in groups is a widespread phenomenon in many animal taxa. The reduction of predation risk is thought to be an important cause for the formation of groups. Consequently, grouping behavior is particularly pronounced during vulnerable life stages, i.e., as juveniles. However, group living does not only provide benefits but also imposes costs on group members, e.g., increased competition for food. Thus, benefits of grouping behavior might not be evident when predation risk is absent. The adaptive significance of living and also developing in a group independent from predation risk has received relatively little attention although this might have important implications on the evolution and maintenance of group living. The first aim of the present study was to examine whether the social environment affects juvenile performance in the cichlid fish Pelvicachromis taeniatus and, secondly, whether kinship affects social behavior. Kin selection theory predicts benefits from grouping with kin. Here, we demonstrate that juveniles reared in a group grow on average faster compared to juveniles reared in isolation under standardized laboratory conditions without predation risk. Furthermore, we found significant differences in social behavior between juveniles reared in a group and reared in isolation. Fish reared in isolation were significantly more aggressive and less willing to shoal than group-reared fish. As expected, genetic relatedness influenced social behavior in group-reared fish as well: dyads of juveniles consisting of kin showed increased group cohesiveness compared to non-kin dyads. We discuss the potential benefits of group living in general and living with kin in particular.},
}
@article {pmid24496091,
year = {2014},
author = {Gardner, A},
title = {Genomic imprinting and the units of adaptation.},
journal = {Heredity},
volume = {113},
number = {2},
pages = {104-111},
doi = {10.1038/hdy.2013.128},
pmid = {24496091},
issn = {1365-2540},
mesh = {*Adaptation, Biological ; Algorithms ; Biological Evolution ; Female ; Genetic Fitness ; Genome ; *Genomic Imprinting ; Genomics ; Humans ; Male ; Models, Genetic ; Selection, Genetic ; },
abstract = {Two guiding principles identify which biological entities are able to evolve adaptations. Williams' principle holds that, in order for an entity to evolve adaptations, there must be selection between such entities. Maynard Smith's principle holds that, in order for an entity to evolve adaptations, selection within such entities must be absent or negligible. However, although the kinship theory of genomic imprinting suggests that parent-of-origin-specific gene expression evolves as a consequence of natural selection acting between--rather than within--individuals, it evades adaptive interpretation at the individual level and is instead viewed as an outcome of an intragenomic conflict of interest between an individual's genes. Here, I formalize the idea that natural selection drives intragenomic conflicts of interest between genes originating from different parents. Specifically, I establish mathematical links between the dynamics of natural selection and the idea of the gene as an intentional, inclusive-fitness-maximizing agent, and I clarify the role that information about parent of origin plays in mediating conflicts of interest between genes residing in the same genome. These results highlight that the suppression of divisive information may be as important as the suppression of lower levels of selection in maintaining the integrity of units of adaptation.},
}
@article {pmid24488971,
year = {2014},
author = {Harpur, BA and Kent, CF and Molodtsova, D and Lebon, JM and Alqarni, AS and Owayss, AA and Zayed, A},
title = {Population genomics of the honey bee reveals strong signatures of positive selection on worker traits.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {111},
number = {7},
pages = {2614-2619},
doi = {10.1073/pnas.1315506111},
pmid = {24488971},
issn = {1091-6490},
mesh = {Adaptation, Biological/*genetics ; Animals ; Base Sequence ; Bees/*genetics ; *Biological Evolution ; *Genetic Variation ; *Hierarchy, Social ; *Metagenomics ; Molecular Sequence Data ; *Selection, Genetic ; Sequence Analysis, DNA ; },
abstract = {Most theories used to explain the evolution of eusociality rest upon two key assumptions: mutations affecting the phenotype of sterile workers evolve by positive selection if the resulting traits benefit fertile kin, and that worker traits provide the primary mechanism allowing social insects to adapt to their environment. Despite the common view that positive selection drives phenotypic evolution of workers, we know very little about the prevalence of positive selection acting on the genomes of eusocial insects. We mapped the footprints of positive selection in Apis mellifera through analysis of 40 individual genomes, allowing us to identify thousands of genes and regulatory sequences with signatures of adaptive evolution over multiple timescales. We found Apoidea- and Apis-specific genes to be enriched for signatures of positive selection, indicating that novel genes play a disproportionately large role in adaptive evolution of eusocial insects. Worker-biased proteins have higher signatures of adaptive evolution relative to queen-biased proteins, supporting the view that worker traits are key to adaptation. We also found genes regulating worker division of labor to be enriched for signs of positive selection. Finally, genes associated with worker behavior based on analysis of brain gene expression were highly enriched for adaptive protein and cis-regulatory evolution. Our study highlights the significant contribution of worker phenotypes to adaptive evolution in social insects, and provides a wealth of knowledge on the loci that influence fitness in honey bees.},
}
@article {pmid24486248,
year = {2014},
author = {Simon, B},
title = {Continuous-time models of group selection, and the dynamical insufficiency of kin selection models.},
journal = {Journal of theoretical biology},
volume = {349},
number = {},
pages = {22-31},
doi = {10.1016/j.jtbi.2014.01.030},
pmid = {24486248},
issn = {1095-8541},
mesh = {*Models, Theoretical ; Population Dynamics ; Time Factors ; },
abstract = {Traditionally, the process of group selection has been described mathematically by discrete-time models, and analyzed using tools like the Price equation. This approach makes implicit assumptions about the process that are not valid in general, like the central role of synchronized mass-dispersion and group re-formation events. In many important examples (like hunter-gatherer tribes) there are no mass-dispersion events, and the group-level events that do occur, like fission, fusion, and extinction, occur asynchronously. Examples like these can be fully analyzed by the equations of two-level population dynamics (described here) so their models are dynamically sufficient. However, it will be shown that examples like these cannot be fully analyzed by kin selection (inclusive fitness) methods because kin selection versions of group selection models are not dynamically sufficient. This is a critical mathematical difference between group selection and kin selection models, which implies that the two theories are not mathematically equivalent.},
}
@article {pmid24480612,
year = {2014},
author = {Haig, D},
title = {Interbirth intervals: Intrafamilial, intragenomic and intrasomatic conflict.},
journal = {Evolution, medicine, and public health},
volume = {2014},
number = {1},
pages = {12-17},
doi = {10.1093/emph/eou002},
pmid = {24480612},
issn = {2050-6201},
abstract = {BACKGROUND AND OBJECTIVES: Interbirth intervals (IBIs) mediate a trade-off between child number and child survival. Life history theory predicts that the evolutionarily optimal IBI differs for different individuals whose fitness is affected by how closely a mother spaces her children. The objective of the article is to clarify these conflicts and explore their implications for public health.

CONCLUSIONS AND IMPLICATIONS: The colonization of maternal bodies by offspring cells (fetal microchimerism) raises the possibility that cells of older offspring could extend IBIs by interfering with the implantation of subsequent embryos.},
}
@article {pmid24463521,
year = {2014},
author = {Carazo, P and Tan, CK and Allen, F and Wigby, S and Pizzari, T},
title = {Within-group male relatedness reduces harm to females in Drosophila.},
journal = {Nature},
volume = {505},
number = {7485},
pages = {672-675},
doi = {10.1038/nature12949},
pmid = {24463521},
issn = {1476-4687},
support = {//Wellcome Trust/United Kingdom ; BB/K014544/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; },
mesh = {Animals ; Competitive Behavior/physiology ; *Cooperative Behavior ; Drosophila melanogaster/genetics/*physiology ; Female ; Heredity/physiology ; Longevity/genetics/physiology ; Male ; Models, Biological ; Reproduction/physiology ; Sexual Behavior, Animal/*physiology ; *Siblings ; },
abstract = {To resolve the mechanisms that switch competition to cooperation is key to understanding biological organization. This is particularly relevant for intrasexual competition, which often leads to males harming females. Recent theory proposes that kin selection may modulate female harm by relaxing competition among male relatives. Here we experimentally manipulate the relatedness of groups of male Drosophila melanogaster competing over females to demonstrate that, as expected, within-group relatedness inhibits male competition and female harm. Females exposed to groups of three brothers unrelated to the female had higher lifetime reproductive success and slower reproductive ageing compared to females exposed to groups of three males unrelated to each other. Triplets of brothers also fought less with each other, courted females less intensively and lived longer than triplets of unrelated males. However, associations among brothers may be vulnerable to invasion by minorities of unrelated males: when two brothers were matched with an unrelated male, the unrelated male sired on average twice as many offspring as either brother. These results demonstrate that relatedness can profoundly affect fitness through its modulation of intrasexual competition, as flies plastically adjust sexual behaviour in a manner consistent with kin-selection theory.},
}
@article {pmid24463009,
year = {2014},
author = {Foster, NL and Briffa, M},
title = {Familial strife on the seashore: aggression increases with relatedness in the sea anemone Actinia equina.},
journal = {Behavioural processes},
volume = {103},
number = {},
pages = {243-245},
doi = {10.1016/j.beproc.2014.01.009},
pmid = {24463009},
issn = {1872-8308},
mesh = {Aggression/*psychology ; Animals ; Behavior, Animal/*physiology ; Competitive Behavior ; Sea Anemones/*physiology ; Social Environment ; },
abstract = {Pairwise contests occur when two individuals compete directly over ownership of an indivisible resource. Contests vary in the degree of escalation, some encounters being settled through non-injurious behaviour while others are only resolved after dangerous fighting. Here, we investigate the role of relatedness, assessed using AFLP analysis, on the occurrence of stinging during staged contests in the beadlet sea anemone Actinia equina. Contrary to our expectations, we found that the chance of stinging, and hence the chance of inflicting damage, increased with the degree of relatedness between the two opponents. This result may be explained by the negative relationship between asymmetry in fighting ability and escalation level predicted by theory. We suggest that in order to fully understand how relatedness influences aggression, predictions from kin selection theory should be incorporated with those from contest theory.},
}
@article {pmid24459698,
year = {2014},
author = {Osborne, DL and Hames, R},
title = {A life history perspective on skin cancer and the evolution of skin pigmentation.},
journal = {American journal of physical anthropology},
volume = {153},
number = {1},
pages = {1-8},
pmid = {24459698},
issn = {1096-8644},
mesh = {Adaptation, Physiological ; Age Factors ; *Anthropology, Physical ; *Biological Evolution ; Humans ; *Skin Neoplasms ; *Skin Pigmentation ; Sunlight ; Ultraviolet Rays ; },
abstract = {The ancestral state of human skin pigmentation evolved in response to high ultraviolet radiation (UVR) stress. Some argue that pigmentation evolved to limit folate photolysis, therein limiting neural tube defects. Pigmentation also protects against sunburn which decreases the efficiency of sweating and potentiates skin infection. Pigmentation increases the efficacy of skin as a barrier to infection. Skin cancer has been rejected or minimized as a selective pressure because it is believed to have little or no effect on mortality during reproductive years. This argument ignores evidence of human longevity as a derived life history trait and the adaptive value of investment in offspring and kin, particularly during the post-reproductive lifespan. Opponents argue that lifespan in prehistoric hunter-gatherers was too short to be relevant to the evolution of skin pigmentation. This argument is flawed in that it relies on estimates of longevity at birth rather than adolescence. When appropriate estimates are used, it is clear that human longevity has a deep evolutionary history. We use a life history perspective to demonstrate the value of skin pigmentation as an adaptation to skin cancer with the following points: UVR exposure increases dysregulation of gene expression in skin cells leading to immortal cell lines; cutaneous malignant melanoma (CMM) affects individuals throughout reproductive years; and lifespan was longer than has previously been acknowledged, providing the opportunity for kin selection. This hypothesis is not at odds with the folate or barrier hypotheses. We stress that the evolution of skin pigmentation is complex and is an ongoing process.},
}
@article {pmid24374238,
year = {2014},
author = {Kobayashi, Y and Ohtsuki, H},
title = {Evolution of social versus individual learning in a subdivided population revisited: comparative analysis of three coexistence mechanisms using the inclusive-fitness method.},
journal = {Theoretical population biology},
volume = {92},
number = {},
pages = {78-87},
doi = {10.1016/j.tpb.2013.12.003},
pmid = {24374238},
issn = {1096-0325},
mesh = {Humans ; *Learning ; *Models, Theoretical ; *Social Behavior ; },
abstract = {Learning abilities are categorized into social (learning from others) and individual learning (learning on one's own). Despite the typically higher cost of individual learning, there are mechanisms that allow stable coexistence of both learning modes in a single population. In this paper, we investigate by means of mathematical modeling how the effect of spatial structure on evolutionary outcomes of pure social and individual learning strategies depends on the mechanisms for coexistence. We model a spatially structured population based on the infinite-island framework and consider three scenarios that differ in coexistence mechanisms. Using the inclusive-fitness method, we derive the equilibrium frequency of social learners and the genetic load of social learning (defined as average fecundity reduction caused by the presence of social learning) in terms of some summary statistics, such as relatedness, for each of the three scenarios and compare the results. This comparative analysis not only reconciles previous models that made contradictory predictions as to the effect of spatial structure on the equilibrium frequency of social learners but also derives a simple mathematical rule that determines the sign of the genetic load (i.e. whether or not social learning contributes to the mean fecundity of the population).},
}
@article {pmid24351787,
year = {2013},
author = {Aubin, HJ and Berlin, I and Kornreich, C},
title = {The evolutionary puzzle of suicide.},
journal = {International journal of environmental research and public health},
volume = {10},
number = {12},
pages = {6873-6886},
doi = {10.3390/ijerph10126873},
pmid = {24351787},
issn = {1660-4601},
mesh = {Adaptation, Biological ; Altruism ; Animals ; *Biological Evolution ; Conflict (Psychology) ; Humans ; Risk Factors ; Stress, Psychological ; Suicide/*psychology ; },
abstract = {Mechanisms of self-destruction are difficult to reconcile with evolution's first rule of thumb: survive and reproduce. However, evolutionary success ultimately depends on inclusive fitness. The altruistic suicide hypothesis posits that the presence of low reproductive potential and burdensomeness toward kin can increase the inclusive fitness payoff of self-removal. The bargaining hypothesis assumes that suicide attempts could function as an honest signal of need. The payoff may be positive if the suicidal person has a low reproductive potential. The parasite manipulation hypothesis is founded on the rodent-Toxoplasma gondii host-parasite model, in which the parasite induces a "suicidal" feline attraction that allows the parasite to complete its life cycle. Interestingly, latent infection by T. gondii has been shown to cause behavioral alterations in humans, including increased suicide attempts. Finally, we discuss how suicide risk factors can be understood as nonadaptive byproducts of evolved mechanisms that malfunction. Although most of the mechanisms proposed in this article are largely speculative, the hypotheses that we raise accept self-destructive behavior within the framework of evolutionary theory.},
}
@article {pmid24332540,
year = {2014},
author = {Drescher, K and Nadell, CD and Stone, HA and Wingreen, NS and Bassler, BL},
title = {Solutions to the public goods dilemma in bacterial biofilms.},
journal = {Current biology : CB},
volume = {24},
number = {1},
pages = {50-55},
doi = {10.1016/j.cub.2013.10.030},
pmid = {24332540},
issn = {1879-0445},
support = {//Howard Hughes Medical Institute/United States ; R01 GM065859/GM/NIGMS NIH HHS/United States ; 5R01GM065859/GM/NIGMS NIH HHS/United States ; },
mesh = {*Biofilms ; Chitin/metabolism ; Chitinases/metabolism ; Gene Expression Regulation, Enzymologic ; RNA, Messenger/biosynthesis ; Vibrio cholerae/*physiology ; },
abstract = {Bacteria frequently live in densely populated surface-bound communities, termed biofilms [1-4]. Biofilm-dwelling cells rely on secretion of extracellular substances to construct their communities and to capture nutrients from the environment [5]. Some secreted factors behave as cooperative public goods: they can be exploited by nonproducing cells [6-11]. The means by which public-good-producing bacteria avert exploitation in biofilm environments are largely unknown. Using experiments with Vibrio cholerae, which secretes extracellular enzymes to digest its primary food source, the solid polymer chitin, we show that the public goods dilemma may be solved by two very different mechanisms: cells can produce thick biofilms that confine the goods to producers, or fluid flow can remove soluble products of chitin digestion, denying access to nonproducers. Both processes are unified by limiting the distance over which enzyme-secreting cells provide benefits to neighbors, resulting in preferential benefit to nearby clonemates and allowing kin selection to favor public good production. Our results demonstrate new mechanisms by which the physical conditions of natural habitats can interact with bacterial physiology to promote the evolution of cooperation.},
}
@article {pmid24329934,
year = {2014},
author = {El Mouden, C and André, JB and Morin, O and Nettle, D},
title = {Cultural transmission and the evolution of human behaviour: a general approach based on the Price equation.},
journal = {Journal of evolutionary biology},
volume = {27},
number = {2},
pages = {231-241},
doi = {10.1111/jeb.12296},
pmid = {24329934},
issn = {1420-9101},
mesh = {Altruism ; *Behavior ; *Biological Evolution ; *Cultural Evolution ; Humans ; *Models, Theoretical ; Selection, Genetic ; },
abstract = {Transmitted culture can be viewed as an inheritance system somewhat independent of genes that is subject to processes of descent with modification in its own right. Although many authors have conceptualized cultural change as a Darwinian process, there is no generally agreed formal framework for defining key concepts such as natural selection, fitness, relatedness and altruism for the cultural case. Here, we present and explore such a framework using the Price equation. Assuming an isolated, independently measurable culturally transmitted trait, we show that cultural natural selection maximizes cultural fitness, a distinct quantity from genetic fitness, and also that cultural relatedness and cultural altruism are not reducible to or necessarily related to their genetic counterparts. We show that antagonistic coevolution will occur between genes and culture whenever cultural fitness is not perfectly aligned with genetic fitness, as genetic selection will shape psychological mechanisms to avoid susceptibility to cultural traits that bear a genetic fitness cost. We discuss the difficulties with conceptualizing cultural change using the framework of evolutionary theory, the degree to which cultural evolution is autonomous from genetic evolution, and the extent to which cultural change should be seen as a Darwinian process. We argue that the nonselection components of evolutionary change are much more important for culture than for genes, and that this and other important differences from the genetic case mean that different approaches and emphases are needed for cultural than genetic processes.},
}
@article {pmid24320989,
year = {2014},
author = {Úbeda, F and Ohtsuki, H and Gardner, A},
title = {Ecology drives intragenomic conflict over menopause.},
journal = {Ecology letters},
volume = {17},
number = {2},
pages = {165-174},
doi = {10.1111/ele.12208},
pmid = {24320989},
issn = {1461-0248},
mesh = {Aged ; Aging/genetics ; Animals ; Culture ; Female ; Fertility/genetics/physiology ; Gene Expression Regulation ; *Genome, Human ; Humans ; Male ; Maternal Age ; Menopause/*genetics/physiology ; Middle Aged ; *Models, Genetic ; },
abstract = {Menopause is the transition from reproductive to non-reproductive life well before natural death. Rather than involving a smooth, rapid change, it is normally preceded by a long period of erratic hormonal fluctuation that is accompanied by a plethora of unpleasant symptoms. Here, we (1) suggest that this turbulent period owes to conflict, between a woman's maternally inherited (MI) and paternally inherited (PI) genes, over the trade-off between reproduction and communal care; (2) perform a theoretical analysis to show that this conflict is resolved either through silencing or fluctuating expression of one of the genes; (3) highlight which of the symptoms preceding menopause may result from antagonistic co-evolution of MI and PI genes; (4) argue that ecological differences between ancestral human populations may explain the variability in menopause among different ethnic groups; (5) discuss how these insights may be used to inform family planning and cancer risk assessment based on a woman's ancestral background.},
}
@article {pmid24277978,
year = {2013},
author = {Schaedelin, FC and van Dongen, WF and Wagner, RH},
title = {Non-random brood mixing suggests adoption in a colonial cichlid.},
journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology},
volume = {24},
number = {2},
pages = {},
doi = {10.1093/beheco/ars195},
pmid = {24277978},
issn = {1045-2249},
support = {P 20401//Austrian Science Fund FWF/Austria ; },
abstract = {Parental care of unrelated offspring is widespread but not well understood. We used 11 polymorphic microsatellite loci to investigate the relatedness of fry and parentally caring adults in a 118-nest colony of the socially and genetically monogamous cichlid fish Neolamprologus caudopunctatus in Lake Tanganyika. There was a high proportion of brood mixing, with 59% of 32 broods containing fry unrelated to both parents, and 18% of all 291 sampled fry being unrelated to the breeding pair. There was no evidence of kin selection for adoption because the genetic and foster parents were not more related than expected by chance. Parentage was assigned to 12 adopted fry from 10 broods. Distances traversed by fry varied markedly, from less than one to over 40 meters. The larger distances suggest that at least some brood mixing was instigated by parents transporting portions of their broods in their mouths, as occurs in some cichlids. Further evidence of non-random brood mixing was that foreign fry did not differ in size from their foster siblings within broods, even though they were significantly larger than fry produced by the tending pairs within the colony. These findings suggest that at least some foreign fry had dispersed non-randomly and were adopted by their foster parents. Enlarged broods are known to provide reduced per capita predation, making it potentially adaptive for breeders to adopt unrelated offspring.},
}
@article {pmid24277847,
year = {2013},
author = {Allen, B and Nowak, MA and Wilson, EO},
title = {Limitations of inclusive fitness.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {110},
number = {50},
pages = {20135-20139},
doi = {10.1073/pnas.1317588110},
pmid = {24277847},
issn = {1091-6490},
mesh = {*Biological Evolution ; Data Interpretation, Statistical ; Gene Frequency ; Genetic Fitness/*genetics ; Genetics, Population/*methods ; *Models, Genetic ; Regression Analysis ; *Social Behavior ; },
abstract = {Until recently, inclusive fitness has been widely accepted as a general method to explain the evolution of social behavior. Affirming and expanding earlier criticism, we demonstrate that inclusive fitness is instead a limited concept, which exists only for a small subset of evolutionary processes. Inclusive fitness assumes that personal fitness is the sum of additive components caused by individual actions. This assumption does not hold for the majority of evolutionary processes or scenarios. To sidestep this limitation, inclusive fitness theorists have proposed a method using linear regression. On the basis of this method, it is claimed that inclusive fitness theory (i) predicts the direction of allele frequency changes, (ii) reveals the reasons for these changes, (iii) is as general as natural selection, and (iv) provides a universal design principle for evolution. In this paper we evaluate these claims, and show that all of them are unfounded. If the objective is to analyze whether mutations that modify social behavior are favored or opposed by natural selection, then no aspect of inclusive fitness theory is needed.},
}
@article {pmid24272207,
year = {2014},
author = {Wikberg, EC and Ting, N and Sicotte, P},
title = {Kinship and similarity in residency status structure female social networks in black-and-white colobus monkeys (Colobus vellerosus).},
journal = {American journal of physical anthropology},
volume = {153},
number = {3},
pages = {365-376},
doi = {10.1002/ajpa.22435},
pmid = {24272207},
issn = {1096-8644},
mesh = {Aggression ; Animals ; Behavior, Animal/*physiology ; Colobus/*physiology ; Female ; Ghana ; Grooming ; Male ; *Social Behavior ; Social Dominance ; },
abstract = {Kinship shapes female social networks in many primate populations in which females remain in their natal group to breed. In contrast, it is unclear to which extent kinship affects the social networks in populations with female dispersal. Female Colobus vellerosus show routine facultative dispersal (i.e., some females remain philopatric and others disperse). This dispersal pattern allowed us to evaluate if facultative dispersed females form social networks shaped by an attraction to kin, to social partners with a high resource holding potential, or to similar social partners in terms of maturational stage, dominance rank, and residency status. During 2008 and 2009, we collected behavioral data via focal and ad libitum sampling of 61 females residing in eight groups at Boabeng-Fiema, Ghana. We determined kinship based on partial pedigrees and genotypes at 17 short tandem repeat loci. Kinship influenced coalition and affiliation networks in three groups consisting of long-term resident females with access to a relatively high number of female kin. In contrast, similar residency status was more important than kinship in structuring the affiliation network in one of two groups that contained recent female immigrants. In populations with female dispersal, the occurrence of kin structured social networks may not only depend on the kin composition of groups but also on how long the female kin have resided together. We found no consistent support for females biasing affiliation toward partners with high resource holding potential, possibly due to low levels of contest competition and small inter-individual differences in resource holding potential.},
}
@article {pmid24268409,
year = {2013},
author = {Ross, L and Gardner, A and Hardy, N and West, SA},
title = {Ecology, not the genetics of sex determination, determines who helps in eusocial populations.},
journal = {Current biology : CB},
volume = {23},
number = {23},
pages = {2383-2387},
doi = {10.1016/j.cub.2013.10.013},
pmid = {24268409},
issn = {1879-0445},
mesh = {Animals ; Biological Evolution ; Crustacea ; Female ; *Gender Identity ; *Gene-Environment Interaction ; Hymenoptera ; Male ; Models, Biological ; Mole Rats ; *Selection, Genetic ; Sex Determination Processes/*genetics ; Sex Factors ; *Sex Ratio ; *Social Behavior ; *Social Environment ; Spiders ; },
abstract = {In eusocial species, the sex ratio of helpers varies from female only, in taxa such as the social Hymenoptera (ants, bees, and wasps) [1], to an unbiased mixture of males and females, as in most termites [2]. Hamilton suggested that this difference owes to the haplodiploid genetics of the Hymenoptera leading to females being relatively more related to their siblings [3]. However, it has been argued that Hamilton's hypothesis does not work [4-9] and that the sex of helpers could instead be explained by variation in the ecological factors that favor eusociality [10]. Here we test these two competing hypotheses, which focus on the possible importance of different terms in Hamilton's rule [2, 11], with a comparative study across all sexual eusocial taxa. We find that the sex ratio of helpers (1) shows no significant correlation with whether species are haplodiploid or diploid and (2) shows a strong correlation with the ecological factor that had favored eusociality. Specifically, when the role of helpers is to defend the nest, both males and females help, whereas when the role of helpers is to provide brood care, then helpers are the sex or sexes that provided parental care ancestrally. More generally, our results confirm the ability of kin selection theory to explain the biology of eusocial species, independently of ploidy, and add support to the idea that haplodiploidy has been more important for shaping conflicts within eusocial societies than for explaining its origins [6, 12-19].},
}
@article {pmid24237705,
year = {2014},
author = {Muralidhar, P and de Sá, FP and Haddad, CF and Zamudio, KR},
title = {Kin-bias, breeding site selection and female fitness in a cannibalistic Neotropical frog.},
journal = {Molecular ecology},
volume = {23},
number = {2},
pages = {453-463},
doi = {10.1111/mec.12592},
pmid = {24237705},
issn = {1365-294X},
mesh = {Animals ; Anura/*genetics/*physiology ; Brazil ; Breeding ; Cannibalism ; Female ; Genotype ; Larva ; Likelihood Functions ; Male ; Microsatellite Repeats ; *Reproduction ; Sequence Analysis, DNA ; *Sexual Behavior, Animal ; *Territoriality ; },
abstract = {Resource availability influences sexual selection within populations and determines whether behaviours such as territoriality or resource sharing are adaptive. In Thoropa taophora, a frog endemic to the Atlantic Coastal Rainforest of Brazil, males compete for and defend limited breeding sites while females often share breeding sites with other females; however, sharing breeding sites may involve costs due to cannibalism by conspecific tadpoles. We studied a breeding population of T. taophora to determine (i) whether this species exhibits polygynous mating involving female choice for territorial males and limited breeding resources; (ii) whether limited breeding resources create the potential for male-male cooperation in defence of neighbouring territories; and (iii) whether females sharing breeding sites exhibit kin-biased breeding site choice, possibly driven by fitness losses due to cannibalism among offspring of females sharing sites. We used microsatellites to reconstruct parentage and quantify relatedness at eight breeding sites in our focal population, where these sites are scarce, and in a second population, where sites are abundant. We found that at localities where the appropriate sites for reproduction are spatially limited, the mating system for this species is polygynous, with typically two females sharing a breeding site with a male. We also found that females exhibit negative kin-bias in their choice of breeding sites, potentially to maximize their inclusive fitness by avoiding tadpole cannibalism of highly related kin. Our results indicate that male territorial defence and female site sharing are likely important components of this mating system, and we propose that kinship-dependent avoidance in mating strategies may be more general than previously realized.},
}
@article {pmid24228918,
year = {2013},
author = {Goldsmith, TC},
title = {Arguments against non-programmed aging theories.},
journal = {Biochemistry. Biokhimiia},
volume = {78},
number = {9},
pages = {971-978},
doi = {10.1134/S0006297913090022},
pmid = {24228918},
issn = {1608-3040},
mesh = {Aging/genetics/*physiology ; Animals ; Biological Evolution ; Humans ; Longevity/genetics/physiology ; Species Specificity ; },
abstract = {Until recently, non-programmed theories of biological aging were popular because of the widespread perception that the evolution process could not support the development and retention of programmed aging in mammals. However, newer evolutionary mechanics theories including group selection, kin selection, and evolvability theory support mammal programmed aging, and multiple programmed aging theories have been published based on the new mechanics. Some proponents of non-programmed aging still contend that their non-programmed theories are superior despite the new mechanics concepts. However, as summarized here, programmed theories provide a vastly better fit to empirical evidence and do not suffer from multiple implausible assumptions that are required by non-programmed theories. This issue is important because programmed theories suggest very different mechanisms for the aging process and therefore different mechanisms behind highly age-related diseases and conditions such as cancer, heart disease, and stroke.},
}
@article {pmid24225452,
year = {2014},
author = {Pfefferle, D and Ruiz-Lambides, AV and Widdig, A},
title = {Female rhesus macaques discriminate unfamiliar paternal sisters in playback experiments: support for acoustic phenotype matching.},
journal = {Proceedings. Biological sciences},
volume = {281},
number = {1774},
pages = {20131628},
doi = {10.1098/rspb.2013.1628},
pmid = {24225452},
issn = {1471-2954},
support = {P40 OD012217/OD/NIH HHS/United States ; 8P40OD012217/OD/NIH HHS/United States ; },
mesh = {Acoustic Stimulation ; Animals ; Cues ; Female ; Macaca mulatta/genetics/physiology/*psychology ; Phenotype ; Recognition (Psychology) ; *Vocalization, Animal ; },
abstract = {Widespread evidence exists that when relatives live together, kinship plays a central role in shaping the evolution of social behaviour. Previous studies showed that female rhesus macaques (Macaca mulatta) recognize familiar maternal kin using vocal cues. Recognizing paternal kin might, however, be more difficult as rhesus females mate promiscuously during the possible conception period, most probably concealing paternity. Behavioural observations indicate that semi free-ranging female rhesus macaques prefer to associate with their paternal half-sisters in comparison to unrelated females within the same group, particularly when born within the same age cohort. However, the cues and mechanism/s used in paternal kin discrimination remain under debate. Here, we investigated whether female rhesus macaques use the acoustic modality to discriminate between paternal half-sisters and non-kin, and tested familiarity and phenotype matching as the underlying mechanisms. We found that test females responded more often to calls of paternal half-sisters compared with calls of unrelated females, and that this discrimination ability was independent of the level of familiarity between callers and test females, which provides, to our knowledge, the first evidence for acoustic phenotype matching. Our study strengthens the evidence that female rhesus macaques can recognize their paternal kin, and that vocalizations are used as a cue.},
}
@article {pmid24215887,
year = {2014},
author = {Iritani, R and Iwasa, Y},
title = {Parasite infection drives the evolution of state-dependent dispersal of the host.},
journal = {Theoretical population biology},
volume = {92},
number = {},
pages = {1-13},
doi = {10.1016/j.tpb.2013.10.005},
pmid = {24215887},
issn = {1096-0325},
mesh = {Animals ; *Biological Evolution ; *Host-Parasite Interactions ; *Models, Biological ; Virulence ; },
abstract = {Dispersal plays a fundamental role in shaping the ecological processes such as host-parasite interactions, and the understanding of host dispersal tendency leads to that of parasites. Here, we present the result of our study on how the evolutionarily stable dispersal of a host would depend on parasite infection, considering kin competition among neighbours. We show that the evolving dispersal rate might be higher for susceptible than for infected individuals (S-biased dispersal) or vice versa (I-biased dispersal). S-biased dispersal is favoured by strong virulence affecting competitive ability, by high rate of parasite release during dispersal, and by low virulence for infected emigrants (i.e. low virulence affecting dispersal ability), whereas I-biased dispersal is favoured in the opposite situation. We also discuss population structure or between-deme genetic differentiation of the host measured with Wright's FST. In I-biased dispersal, between-deme genetic differentiation decreases with the infection rate, while in S-biased dispersal, genetic differentiation increases with infection rate.},
}
@article {pmid24211682,
year = {2014},
author = {Lotem, A and Biran-Yoeli, I},
title = {Evolution of learning and levels of selection: a lesson from avian parent-offspring communication.},
journal = {Theoretical population biology},
volume = {91},
number = {},
pages = {58-74},
doi = {10.1016/j.tpb.2013.10.003},
pmid = {24211682},
issn = {1096-0325},
mesh = {*Animal Communication ; Animals ; *Biological Evolution ; Birds/*physiology ; *Learning ; },
abstract = {In recent years, it has become increasingly clear that the evolution of behavior may be better understood as the evolution of the learning mechanisms that produce it, and that such mechanisms should be modeled and tested explicitly. However, this approach, which has recently been applied to animal foraging and decision-making, has rarely been applied to the social and communicative behaviors that are likely to operate in complex social environments and be subject to multi-level selection. Here we use genetic, agent-based evolutionary simulations to explore how learning mechanisms may evolve to adjust the level of nestling begging (offspring signaling of need), and to examine the possible consequences of this process for parent-offspring conflict and communication. In doing so, we also provide the first step-by-step dynamic model of parent-offspring communication. The results confirm several previous theoretical predictions and demonstrate three novel phenomena. First, negatively frequency-dependent group-level selection can generate a stable polymorphism of learning strategies and parental responses. Second, while conventional reinforcement learning models fail to cope successfully with family dynamics at the nest, a newly developed learning model (incorporating behaviors that are consistent with recent experimental results on learning in nestling begging) produced effective learning, which evolved successfully. Third, while kin-selection affects the frequency of the different learning genes, its impact on begging slope and intensity was unexpectedly negligible, demonstrating that evolution is a complex process, and showing that the effect of kin-selection on behaviors that are shaped by learning may not be predicted by simple application of Hamilton's rule.},
}
@article {pmid24171718,
year = {2014},
author = {Smith, J and Van Dyken, JD and Velicer, GJ},
title = {Nonadaptive processes can create the appearance of facultative cheating in microbes.},
journal = {Evolution; international journal of organic evolution},
volume = {68},
number = {3},
pages = {816-826},
doi = {10.1111/evo.12306},
pmid = {24171718},
issn = {1558-5646},
support = {R01 GM07690/GM/NIGMS NIH HHS/United States ; },
mesh = {Adaptation, Physiological/*genetics ; *Evolution, Molecular ; *Models, Genetic ; Mutation ; Myxococcus/*genetics/physiology ; Selection, Genetic ; Spores, Bacterial/genetics ; },
abstract = {Adaptations to social life may take the form of facultative cheating, in which organisms cooperate with genetically similar individuals but exploit others. Consistent with this possibility, many strains of social microbes like Myxococcus bacteria and Dictyostelium amoebae have equal fitness in single-genotype social groups but outcompete other strains in mixed-genotype groups. Here we show that these observations are also consistent with an alternative, nonadaptive scenario: kin selection-mutation balance under local competition. Using simple mathematical models, we show that deleterious mutations that reduce competitiveness within social groups (growth rate, e.g.) without affecting group productivity can create fitness effects that are only expressed in the presence of other strains. In Myxococcus, mutations that delay sporulation may strongly reduce developmental competitiveness. Deleterious mutations are expected to accumulate when high levels of kin selection relatedness relax selection within groups. Interestingly, local resource competition can create nonzero "cost" and "benefit" terms in Hamilton's rule even in the absence of any cooperative trait. Our results show how deleterious mutations can play a significant role even in organisms with large populations and highlight the need to test evolutionary causes of social competition among microbes.},
}
@article {pmid24169647,
year = {2014},
author = {Alemu, SW and Berg, P and Janss, L and Bijma, P},
title = {Indirect genetic effects and kin recognition: estimating IGEs when interactions differ between kin and strangers.},
journal = {Heredity},
volume = {112},
number = {2},
pages = {197-206},
doi = {10.1038/hdy.2013.92},
pmid = {24169647},
issn = {1365-2540},
mesh = {Algorithms ; Breeding ; Computer Simulation ; Genetic Variation ; Humans ; *Models, Genetic ; Monte Carlo Method ; Phenotype ; *Quantitative Trait, Heritable ; Reproducibility of Results ; },
abstract = {Social interactions among individuals are widespread, both in natural and domestic populations. As a result, trait values of individuals may be affected by genes in other individuals, a phenomenon known as indirect genetic effects (IGEs). IGEs can be estimated using linear mixed models. The traditional IGE model assumes that an individual interacts equally with all its partners, whether kin or strangers. There is abundant evidence, however, that individuals behave differently towards kin as compared with strangers, which agrees with predictions from kin-selection theory. With a mix of kin and strangers, therefore, IGEs estimated from a traditional model may be incorrect, and selection based on those estimates will be suboptimal. Here we investigate whether genetic parameters for IGEs are statistically identifiable in group-structured populations when IGEs differ between kin and strangers, and develop models to estimate such parameters. First, we extend the definition of total breeding value and total heritable variance to cases where IGEs depend on relatedness. Next, we show that the full set of genetic parameters is not identifiable when IGEs differ between kin and strangers. Subsequently, we present a reduced model that yields estimates of the total heritable effects on kin, on non-kin and on all social partners of an individual, as well as the total heritable variance for response to selection. Finally we discuss the consequences of analysing data in which IGEs depend on relatedness using a traditional IGE model, and investigate group structures that may allow estimation of the full set of genetic parameters when IGEs depend on kin.},
}
@article {pmid24167305,
year = {2013},
author = {Young, AJ and Bennett, NC},
title = {Intra-sexual selection in cooperative mammals and birds: why are females not bigger and better armed?.},
journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences},
volume = {368},
number = {1631},
pages = {20130075},
doi = {10.1098/rstb.2013.0075},
pmid = {24167305},
issn = {1471-2970},
support = {BB/H022716/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; //Biotechnology and Biological Sciences Research Council/United Kingdom ; },
mesh = {Animals ; *Cooperative Behavior ; Desert Climate ; Female ; Male ; Mole Rats/anatomy & histology/genetics/*physiology ; Reproduction/genetics/*physiology ; Selection, Genetic/genetics/*physiology ; Sex Characteristics ; *Social Dominance ; },
abstract = {In cooperatively breeding mammals and birds, intra-sexual reproductive competition among females may often render variance in reproductive success higher among females than males, leading to the prediction that intra-sexual selection in such species may have yielded the differential exaggeration of competitive traits among females. However, evidence to date suggests that female-biased reproductive variance in such species is rarely accompanied by female-biased sexual dimorphisms. We illustrate the problem with data from wild Damaraland mole-rat, Fukomys damarensis, societies: the variance in lifetime reproductive success among females appears to be higher than that among males, yet males grow faster, are much heavier as adults and sport larger skulls and incisors (the weapons used for fighting) for their body lengths than females, suggesting that intra-sexual selection has nevertheless acted more strongly on the competitive traits of males. We then consider potentially general mechanisms that could explain these disparities by tempering the relative intensity of selection for competitive trait exaggeration among females in cooperative breeders. Key among these may be interactions with kin selection that could nevertheless render the variance in inclusive fitness lower among females than males, and fundamental aspects of the reproductive biology of females that may leave reproductive conflict among females more readily resolved without overt physical contests.},
}
@article {pmid24167148,
year = {2014},
author = {Cooper, LC and Desjonqueres, C and Leather, SR},
title = {Cannibalism in the pea aphid, Acyrthosiphon pisum.},
journal = {Insect science},
volume = {21},
number = {6},
pages = {750-758},
doi = {10.1111/1744-7917.12070},
pmid = {24167148},
issn = {1744-7917},
mesh = {Animals ; Aphids/genetics/*physiology ; *Cannibalism ; Life Cycle Stages ; Peas/parasitology/physiology ; *Starvation ; },
abstract = {Previous observations of cannibalism have been made in the aphid Acyrthosiphon pisum (L.): this article seeks to quantify factors contributing to such behaviors. We observed and quantified the responses of a number of clones and life stages to varying levels of starvation, in the form of increasingly desiccated Vica faba L. plants (receiving 50, 25, or 10 mL every second day) or a complete absence of host plant. We found that, while the longest incidences of cannibalism are carried out by juveniles (F = 3.45, P = 0.019, df = 3) and targeted at adults, the starvation treatments had the most significant effect on the prevalence of cannibalism in mature A. pisum (F = 2.24, P = 0.025, df = 9). Furthermore, there was no difference between the prevalence or duration of cannibalistic activities within and between different clones (P ≥ 0.05 in all cases), though juveniles were more likely to target unrelated aphids (V = 6 112, P = 0.011), and spent more time feeding on aphids from the same culture (V = 6 062, P = 0.018).},
}
@article {pmid24166925,
year = {2013},
author = {Mace, R},
title = {Cooperation and conflict between women in the family.},
journal = {Evolutionary anthropology},
volume = {22},
number = {5},
pages = {251-258},
doi = {10.1002/evan.21374},
pmid = {24166925},
issn = {1520-6505},
mesh = {Conflict (Psychology) ; *Cooperative Behavior ; *Family Characteristics ; Female ; Humans ; Male ; Reproduction ; *Social Behavior ; *Women ; },
abstract = {Here I review recent research on reproductive conflict between females in families and how it influences their reproductive behaviour. Kin selection can favor cooperation between parent and offspring, siblings, or unrelated co-residents who share interests in other family members such as grand-offspring. However, these are also the individuals most likely to be sharing resources, and so conflict can also emerge. While substantial interest has arisen in evolutionary anthropology, especially over the last two decades, in the possibility of cooperative breeding in humans, less attention has been paid to reproductive conflict among female kin. Communal breeding in animals is generally understood as emerging from competition over the resources needed to breed. Competition for household resources is a problem that also faces human families. Models suggest that in some circumstances, inclusive fitness can be maximized by sharing reproduction rather than harming relatives by fighting with them, even if the shares that emerge are not equal. Thus, competition and cooperation turn out to be strongly related to each other. Reproductive competition within and between families may have underpinned the biological evolution of fertility patterns (such as menopause) and the cultural evolution of marriage, residence, and inheritance norms (such as late male marriage or primogeniture), which can enhance cooperation and minimize the observed incidence of such conflicts.},
}
@article {pmid24166924,
year = {2013},
author = {Widdig, A},
title = {The Impact of male reproductive skew on kin structure and sociality in multi-male groups.},
journal = {Evolutionary anthropology},
volume = {22},
number = {5},
pages = {239-250},
doi = {10.1002/evan.21366},
pmid = {24166924},
issn = {1520-6505},
mesh = {Animals ; Breeding ; Cercopithecinae ; Female ; Male ; *Reproduction ; *Sexual Behavior, Animal ; Siblings ; *Social Behavior ; },
abstract = {Patterns of within-group relatedness are expected to affect the prospects for cooperation among group members through kin selection. It has long been established that dispersal patterns determine the availability of kin and there is ample evidence of matrilineal kin biases in social behavior across primate species. However, in 1979, Jeanne Altmann(1) suggested that mating patterns also influence the structure of within-group relatedness; high male reproductive skew and the frequent replacement of breeding males leads to relatively high levels of paternal relatedness and age-structured paternal sibships within groups. As a consequence of frequent replacement of breeding males, relatedness among offspring of a given female will be reduced to the half- rather than full-sibling level. Depending on the number of sires and degree of relatedness among mothers, members of the same birth cohort may be as closely related as maternal siblings. If animals are able to recognize their paternal kin and exhibit biases in favor of them, this may influence the distribution of cooperation and the intensity of competition within groups of primates. Here, I summarize the evidence that serves as the basis for Altmann's predictions and review evidence regarding whether or not the availability of paternal kin also leads to paternal kin bias among primates.},
}
@article {pmid24152004,
year = {2013},
author = {McLeod, DV and Wild, G},
title = {Ecological constraints influence the emergence of cooperative breeding when population dynamics determine the fitness of helpers.},
journal = {Evolution; international journal of organic evolution},
volume = {67},
number = {11},
pages = {3221-3232},
doi = {10.1111/evo.12188},
pmid = {24152004},
issn = {1558-5646},
mesh = {Animals ; *Biological Evolution ; *Cooperative Behavior ; Genetic Fitness ; Models, Biological ; Population Density ; Reproduction ; },
abstract = {Cooperative breeding is a system in which certain individuals facilitate the production of offspring by others. The ecological constraints hypothesis states that ecological conditions deter individuals from breeding independently, and so individuals breed cooperatively to make the best of a bad situation. Current theoretical support for the ecological constraints hypothesis is lacking. We formulate a mathematical model that emphasizes the underlying ecology of cooperative breeders. Our goal is to derive theoretical support for the ecological constraints hypothesis using an ecological model of population dynamics. We consider a population composed of two kinds of individuals, nonbreeders (auxiliaries) and breeders. We suppose that help provided by an auxiliary increases breeder fecundity, but reduces the probability with which the auxiliary becomes a breeder. Our main result is a condition that guarantees success of auxiliary help. We predict that increasing the cost of dispersal promotes helping, in agreement with verbal theory. We also predict that increasing breeder mortality can either hinder helping (at high population densities), or promote it (at low population densities). We conclude that ecological constraints can exert influence over the evolution of auxiliary help when population dynamics are considered; moreover, that influence need not coincide with direct fitness benefits as previously found.},
}
@article {pmid24132311,
year = {2013},
author = {Riehl, C},
title = {Evolutionary routes to non-kin cooperative breeding in birds.},
journal = {Proceedings. Biological sciences},
volume = {280},
number = {1772},
pages = {20132245},
doi = {10.1098/rspb.2013.2245},
pmid = {24132311},
issn = {1471-2954},
mesh = {Animal Distribution ; Animals ; *Biological Evolution ; Birds/genetics/*physiology ; *Nesting Behavior ; Selection, Genetic ; *Social Behavior ; },
abstract = {Cooperatively breeding animals live in social groups in which some individuals help to raise the offspring of others, often at the expense of their own reproduction. Kin selection--when individuals increase their inclusive fitness by aiding genetic relatives--is a powerful explanation for the evolution of cooperative breeding, particularly because most groups consist of family members. However, recent molecular studies have revealed that many cooperative groups also contain unrelated immigrants, and the processes responsible for the formation and maintenance of non-kin coalitions are receiving increasing attention. Here, I provide the first systematic review of group structure for all 213 species of cooperatively breeding birds for which data are available. Although the majority of species (55%) nest in nuclear family groups, cooperative breeding by unrelated individuals is more common than previously recognized: 30% nest in mixed groups of relatives and non-relatives, and 15% nest primarily with non-relatives. Obligate cooperative breeders are far more likely to breed with non-kin than are facultative cooperators, indicating that when constraints on independent breeding are sufficiently severe, the direct benefits of group membership can substitute for potential kin-selected benefits. I review three patterns of dispersal that give rise to social groups with low genetic relatedness, and I discuss the selective pressures that favour the formation of such groups. Although kin selection has undoubtedly been crucial to the origin of most avian social systems, direct benefits have subsequently come to play a predominant role in some societies, allowing cooperation to persist despite low genetic relatedness.},
}
@article {pmid24132100,
year = {2013},
author = {Herbers, JM},
title = {50 Years on: the legacy of William Donald Hamilton.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130792},
doi = {10.1098/rsbl.2013.0792},
pmid = {24132100},
issn = {1744-957X},
mesh = {Animals ; Biological Evolution ; Biology/*history ; *Genetic Fitness ; History, 20th Century ; Humans ; },
}
@article {pmid24132096,
year = {2013},
author = {Tsuji, K},
title = {Kin selection, species richness and community.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130491},
doi = {10.1098/rsbl.2013.0491},
pmid = {24132096},
issn = {1744-957X},
mesh = {Animals ; Ants/*physiology ; Behavior, Animal ; Biological Evolution ; Competitive Behavior ; Ecology ; Female ; *Genetic Fitness ; Insecta ; Male ; Population Dynamics ; Reproduction ; Selection, Genetic ; Sexual Behavior, Animal ; Social Behavior ; *Species Specificity ; },
abstract = {Can evolutionary and ecological dynamics operating at one level of the biological hierarchy affect the dynamics and structure at other levels? In social insects, strong hostility towards unrelated individuals can evolve as a kin-selected counter-adaptation to intraspecific social parasitism. This aggression in turn might cause intraspecific competition to predominate over interspecific competition, permitting coexistence with other social insect species. In other words, kin selection-a form of intra-population dynamics-might enhance the species richness of the community, a higher-level structure. The converse effect, from higher to lower levels, might also operate, whereby strong interspecific competition may limit the evolution of selfish individual traits. If the latter effect were to prove more important, it would challenge the common view that intra-population dynamics (via individual or gene selection) is the main driver of evolution.},
}
@article {pmid24132095,
year = {2013},
author = {Kamel, SJ and Grosberg, RK},
title = {Kinship and the evolution of social behaviours in the sea.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130454},
doi = {10.1098/rsbl.2013.0454},
pmid = {24132095},
issn = {1744-957X},
mesh = {Animals ; Biological Evolution ; Clutch Size/physiology ; Ecology ; Ecosystem ; Female ; Invertebrates/anatomy & histology/*physiology ; Life Cycle Stages/physiology ; Male ; Marine Biology ; Models, Biological ; Oceans and Seas ; Population Dynamics ; *Sexual Behavior, Animal ; *Social Behavior ; },
abstract = {Until recently, little attention has been paid to the existence of kin structure in the sea, despite the fact that many marine organisms are sessile or sedentary. This lack of attention to kin structure, and its impacts on social evolution, historically stems from the pervasive assumption that the dispersal of gametes and larvae is almost always sufficient to prevent any persistent associations of closely related offspring or adults. However, growing evidence, both theoretical and empirical, casts doubt on the generality of this assumption, not only in species with limited dispersal, but also in species with long dispersive phases. Moreover, many marine organisms either internally brood their progeny or package them in nurseries, both of which provide ample opportunities for kinship to influence the nature and outcomes of social interactions among family members. As the evidence for kin structure within marine populations mounts, it follows that kin selection may play a far greater role in the evolution of both behaviours and life histories of marine organisms than is presently appreciated.},
}
@article {pmid24132094,
year = {2013},
author = {Boomsma, JJ and d'Ettorre, P},
title = {Nice to kin and nasty to non-kin: revisiting Hamilton's early insights on eusociality.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130444},
doi = {10.1098/rsbl.2013.0444},
pmid = {24132094},
issn = {1744-957X},
mesh = {Altruism ; Animals ; Ants ; *Behavior, Animal ; Biological Evolution ; Breeding ; Genetic Fitness ; Genetic Variation ; Humans ; Insecta ; Male ; Models, Genetic ; Selection, Genetic ; *Social Behavior ; },
abstract = {When helping behaviour is costly, Hamiltonian logic implies that animals need to direct helpful acts towards kin, so that indirect fitness benefits justify the costs. We revisit inferences about nepotism and aggression in Hamilton's 1964 paper to argue that he overestimated the general significance of nepotism, but that other issues that he raised continue to suggest novel research agendas today. We now know that nepotism in eusocial insects is rare, because variation in genetic recognition cues is insufficient. A lower proportion of individuals breeding and larger clutch sizes selecting for a more uniform colony odour may explain this. Irreversible worker sterility can induce both the fiercest possible aggression and the highest likelihood of helping random distant kin, but these Hamiltonian contentions still await large-scale testing in social animals.},
}
@article {pmid24132093,
year = {2013},
author = {Tsutsui, ND},
title = {Dissecting ant recognition systems in the age of genomics.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130416},
doi = {10.1098/rsbl.2013.0416},
pmid = {24132093},
issn = {1744-957X},
mesh = {Animals ; Ants/*physiology ; *Biological Evolution ; Cues ; Female ; Genomics ; Hydrocarbons/chemistry ; Insect Proteins/*genetics ; Male ; Perception ; Phenotype ; *Recognition (Psychology) ; Reproduction/*physiology ; Sex Attractants/*genetics ; *Sexual Behavior, Animal ; Signal Transduction ; Social Behavior ; },
abstract = {Hamilton is probably best known for his seminal work demonstrating the role of kin selection in social evolution. His work made it clear that, for individuals to direct their altruistic behaviours towards appropriate recipients (kin), mechanisms must exist for kin recognition. In the social insects, colonies are typically comprised of kin, and colony recognition cues are used as proxies for kinship cues. Recent years have brought rapid advances in our understanding of the genetic and molecular mechanisms that are used for this process. Here, I review some of the most notable advances, particularly the contributions from recent ant genome sequences and molecular biology.},
}
@article {pmid24132092,
year = {2013},
author = {Thompson, GJ and Hurd, PL and Crespi, BJ},
title = {Genes underlying altruism.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130395},
doi = {10.1098/rsbl.2013.0395},
pmid = {24132092},
issn = {1744-957X},
mesh = {Alleles ; *Altruism ; Animals ; Behavior, Animal ; Biological Evolution ; *Genetic Fitness ; Hierarchy, Social ; Humans ; Insecta/*genetics ; Models, Genetic ; Oxytocin/metabolism ; Phenotype ; Polymorphism, Genetic ; Selection, Genetic ; *Social Behavior ; },
abstract = {William D. Hamilton postulated the existence of 'genes underlying altruism', under the rubric of inclusive fitness theory, a half-century ago. Such genes are now poised for discovery. In this article, we develop a set of intuitive criteria for the recognition and analysis of genes for altruism and describe the first candidate genes affecting altruism from social insects and humans. We also provide evidence from a human population for genetically based trade-offs, underlain by oxytocin-system polymorphisms, between alleles for altruism and alleles for non-social cognition. Such trade-offs between self-oriented and altruistic behaviour may influence the evolution of phenotypic diversity across all social animals.},
}
@article {pmid24132089,
year = {2013},
author = {Costa, JT},
title = {Hamiltonian inclusive fitness: a fitter fitness concept.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130335},
doi = {10.1098/rsbl.2013.0335},
pmid = {24132089},
issn = {1744-957X},
mesh = {Altruism ; Animals ; Biological Evolution ; Biology/*history ; *Genetic Fitness ; Genomic Imprinting ; History, 19th Century ; History, 20th Century ; Humans ; Insecta ; *Models, Biological ; Selection, Genetic ; Social Behavior ; },
abstract = {In 1963-1964 W. D. Hamilton introduced the concept of inclusive fitness, the only significant elaboration of Darwinian fitness since the nineteenth century. I discuss the origin of the modern fitness concept, providing context for Hamilton's discovery of inclusive fitness in relation to the puzzle of altruism. While fitness conceptually originates with Darwin, the term itself stems from Spencer and crystallized quantitatively in the early twentieth century. Hamiltonian inclusive fitness, with Price's reformulation, provided the solution to Darwin's 'special difficulty'-the evolution of caste polymorphism and sterility in social insects. Hamilton further explored the roles of inclusive fitness and reciprocation to tackle Darwin's other difficulty, the evolution of human altruism. The heuristically powerful inclusive fitness concept ramified over the past 50 years: the number and diversity of 'offspring ideas' that it has engendered render it a fitter fitness concept, one that Darwin would have appreciated.},
}
@article {pmid24132088,
year = {2013},
author = {Wenseleers, T and Helanterä, H and Alves, DA and Dueñez-Guzmán, E and Pamilo, P},
title = {Towards greater realism in inclusive fitness models: the case of worker reproduction in insect societies.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130334},
doi = {10.1098/rsbl.2013.0334},
pmid = {24132088},
issn = {1744-957X},
mesh = {Animals ; Bees ; *Behavior, Animal ; Biological Evolution ; Female ; *Genetic Fitness ; Hierarchy, Social ; Insecta ; Male ; Models, Genetic ; Reproduction/genetics ; Sex Factors ; Sex Ratio ; Sexual Behavior, Animal ; Social Behavior ; },
abstract = {The conflicts over sex allocation and male production in insect societies have long served as an important test bed for Hamilton's theory of inclusive fitness, but have for the most part been considered separately. Here, we develop new coevolutionary models to examine the interaction between these two conflicts and demonstrate that sex ratio and colony productivity costs of worker reproduction can lead to vastly different outcomes even in species that show no variation in their relatedness structure. Empirical data on worker-produced males in eight species of Melipona bees support the predictions from a model that takes into account the demographic details of colony growth and reproduction. Overall, these models contribute significantly to explaining behavioural variation that previous theories could not account for.},
}
@article {pmid24132087,
year = {2013},
author = {Hall, DW and Yi, SV and Goodisman, MA},
title = {Kin selection, genomics and caste-antagonistic pleiotropy.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130309},
doi = {10.1098/rsbl.2013.0309},
pmid = {24132087},
issn = {1744-957X},
mesh = {Animals ; Ants ; Bees ; Biological Evolution ; Evolution, Molecular ; Genetic Variation ; Genome ; Genomics ; Genotype ; Insecta ; Models, Genetic ; Phenotype ; Polymorphism, Genetic ; Reproduction/*genetics ; Sexual Behavior, Animal ; *Social Behavior ; Wasps ; },
abstract = {Kin selection is a fundamentally important process that affects the evolution of social behaviours. The genomics revolution now provides the opportunity to test kin selection theory using genomic data. In this commentary, we discuss previous studies that explored the link between kin selection and patterns of variation within the genome. We then present a new theory aimed at understanding the evolution of genes involved in the development of social insects. Specifically, we investigate caste-antagonistic pleiotropy, which occurs when the phenotypes of distinct castes are optimized by different genotypes at a single locus. We find that caste-antagonistic pleiotropy leads to narrow regions where polymorphism can be maintained. Furthermore, multiple mating by queens reduces the region in which worker-favoured alleles fix, which suggests that multiple mating impedes worker caste evolution. We conclude by discussing ways to test these and other facets of kin selection using newly emerging genomic data.},
}
@article {pmid24132086,
year = {2013},
author = {Haig, D},
title = {Imprinted green beards: a little less than kin and more than kind.},
journal = {Biology letters},
volume = {9},
number = {6},
pages = {20130199},
doi = {10.1098/rsbl.2013.0199},
pmid = {24132086},
issn = {1744-957X},
mesh = {Algorithms ; *Alleles ; Animals ; DNA/*chemistry ; *Genomic Imprinting ; Humans ; Models, Genetic ; Multigene Family ; Mutation ; Probability ; RNA/*chemistry ; RNA, Small Interfering/metabolism ; },
abstract = {RNA is complementary to the DNA sequence from which it is transcribed. Therefore, interactions between DNA and RNA provide a simple mechanism of genetic self-detection within nuclei. Imprinted RNAs could enable alleles of maternal and paternal origin to detect whether they are the same (homozygous) or different (heterozygous), and thereby provide strategic information about expected relatedness to siblings.},
}
@article {pmid24118386,
year = {2013},
author = {Łukasik, P and Guo, H and van Asch, M and Ferrari, J and Godfray, HC},
title = {Protection against a fungal pathogen conferred by the aphid facultative endosymbionts Rickettsia and Spiroplasma is expressed in multiple host genotypes and species and is not influenced by co-infection with another symbiont.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {12},
pages = {2654-2661},
doi = {10.1111/jeb.12260},
pmid = {24118386},
issn = {1420-9101},
support = {BB/E010857/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; },
mesh = {Animals ; Aphids/genetics/*microbiology ; Fungi/*pathogenicity ; Genotype ; *Host-Pathogen Interactions ; Rickettsia/*pathogenicity ; Spiroplasma/*pathogenicity ; *Symbiosis ; },
abstract = {Many insects harbour facultative endosymbiotic bacteria, often more than one type at a time. These symbionts can have major effects on their hosts' biology, which may be modulated by the presence of other symbiont species and by the host's genetic background. We investigated these effects by transferring two sets of facultative endosymbionts (one Hamiltonella and Rickettsia, the other Hamiltonella and Spiroplasma) from naturally double-infected pea aphid hosts into five novel host genotypes of two aphid species. The symbionts were transferred either together or separately. We then measured aphid fecundity and susceptibility to an entomopathogenic fungus. The pathogen-protective phenotype conferred by the symbionts Rickettsia and Spiroplasma varied among host genotypes, but was not influenced by co-infection with Hamiltonella. Fecundity varied across single and double infections and between symbiont types, aphid genotypes and species. Some host genotypes benefit from harbouring more than one symbiont type.},
}
@article {pmid24118371,
year = {2013},
author = {Taylor, TB and Rodrigues, AM and Gardner, A and Buckling, A},
title = {The social evolution of dispersal with public goods cooperation.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {12},
pages = {2644-2653},
doi = {10.1111/jeb.12259},
pmid = {24118371},
issn = {1420-9101},
mesh = {*Biological Evolution ; *Cooperative Behavior ; Humans ; *Social Behavior ; },
abstract = {Selection can favour the evolution of individually costly dispersal if this alleviates competition between relatives. However, conditions that favour altruistic dispersal also mediate selection for other social behaviours, such as public goods cooperation, which in turn is likely to mediate dispersal evolution. Here, we investigate - both experimentally (using bacteria) and theoretically - how social habitat heterogeneity (i.e. the distribution of public goods cooperators and cheats) affects the evolution of dispersal. In addition to recovering the well-known theoretical result that the optimal level of dispersal increases with genetic relatedness of patch mates, we find both mathematically and experimentally that dispersal is always favoured when average patch occupancy is low, but when average patch occupancy is high, the presence of public goods cheats greatly alters selection for dispersal. Specifically, when public goods cheats are localized to the home patch, higher dispersal rates are favoured, but when cheats are present throughout available patches, lower dispersal rates are favoured. These results highlight the importance of other social traits in driving dispersal evolution.},
}
@article {pmid24118247,
year = {2013},
author = {Krupp, DB},
title = {How to distinguish altruism from spite (and why we should bother).},
journal = {Journal of evolutionary biology},
volume = {26},
number = {12},
pages = {2746-2749},
doi = {10.1111/jeb.12253},
pmid = {24118247},
issn = {1420-9101},
mesh = {*Altruism ; Humans ; *Social Behavior ; },
abstract = {Social behaviour is often described as altruistic, spiteful, selfish or mutually beneficial. These terms are appealing, but it has not always been clear how they are defined and what purpose they serve. Here, I show that the distinctions among them arise from the ways in which fitness is partitioned: none can be drawn when the fitness consequences of an action are wholly aggregated, but they manifest clearly when the consequences are partitioned into primary and secondary (neighbourhood) effects. I argue that the primary interaction is the principal source of adaptive design, because (i) it is this interaction that determines the fit of an adaptation and (ii) it is the actor and primary recipients whom an adaptation foremost affects. The categories of social action are thus instrumental to any account of evolved function.},
}
@article {pmid24100232,
year = {2013},
author = {Amsalem, E and Shpigler, H and Bloch, G and Hefetz, A},
title = {Dufour's gland secretion, sterility and foraging behavior: correlated behavior traits in bumblebee workers.},
journal = {Journal of insect physiology},
volume = {59},
number = {12},
pages = {1250-1255},
doi = {10.1016/j.jinsphys.2013.09.007},
pmid = {24100232},
issn = {1879-1611},
mesh = {Animals ; Bees/*physiology ; *Behavior, Animal ; Bodily Secretions ; Esters/*metabolism ; Female ; Infertility ; },
abstract = {Bombus terrestris colonies go through two major phases: the "pre-competition phase" in which the queen is the sole reproducer and aggression is rare, and the "competition phase" in which workers aggressively compete over reproduction. Conflicts over reproduction are partially regulated by a group of octyl esters that are produced in Dufour's gland of reproductively subordinate workers and protect them from being aggressed. However, workers possess octyl esters even before overt aggression occurs, raising the question of why produce the ester-signal before it is functionally necessary? In most insect societies, foragers show reduced aggression and low dominance rank. We hypothesize that ester production in B. terrestris is not only correlated with sterility but also with foraging, signaling cooperative behavior by subordinate workers. Such a signal helps to maintain social organization, reduce the cost of fights between reproductives and helpers, and increase colony productivity, enabling subordinates to gain greater inclusive fitness. We demonstrate that foragers produce larger amounts of esters compared to non-foragers, and that their amounts positively correlate with foraging efforts. We further suggest that task performance, potential fecundity, and aggression are interlinked, and that worker-worker interactions are involved in regulating foraging behavior. B. terrestris, being an intermediate phase between primitive and derived eusocial insects, provides an excellent model for understanding the evolution of early phases of eusociality. Our results, combined with those in primitively eusocial wasps, suggest that at early stages of social evolution, reproduction was regulated by a "primordial division of labor", that comprised foragers and reproducers, which further evolved to a more complex division of labor, a hallmark of eusociality.},
}
@article {pmid24094343,
year = {2013},
author = {Tonsor, SJ and Elnaccash, TW and Scheiner, SM},
title = {Developmental instability is genetically correlated with phenotypic plasticity, constraining heritability, and fitness.},
journal = {Evolution; international journal of organic evolution},
volume = {67},
number = {10},
pages = {2923-2935},
doi = {10.1111/evo.12175},
pmid = {24094343},
issn = {1558-5646},
mesh = {Adaptation, Biological/genetics/*physiology ; Analysis of Variance ; Arabidopsis/genetics/*growth & development/metabolism ; *Biological Evolution ; *Environment ; Genetic Fitness/*genetics ; Genotype ; Nitrogen/metabolism ; *Phenotype ; },
abstract = {Although adaptive plasticity would seem always to be favored by selection, it occurs less often than expected. This lack of ubiquity suggests that there must be trade-offs, costs, or limitations associated with plasticity. Yet, few costs have been found. We explore one type of limitation, a correlation between plasticity and developmental instability, and use quantitative genetic theory to show why one should expect a genetic correlation. We test that hypothesis using the Landsberg erecta × Cape Verde Islands recombinant inbred lines (RILs) of Arabidopsis thaliana. RILs were grown at four different nitrogen (N) supply levels that span the range of N availabilities previously documented in North American field populations. We found a significant multivariate relationship between the cross-environment trait plasticity and the within-environment, within-RIL developmental instability across 13 traits. This genetic covariation between plasticity and developmental instability has two costs. First, theory predicts diminished fitness for highly plastic lines under stabilizing selection, because their developmental instability and variance around the optimum phenotype will be greater compared to nonplastic genotypes. Second, empirically the most plastic traits exhibited heritabilities reduced by 57% on average compared to nonplastic traits. This demonstration of potential costs in inclusive fitness and heritability provoke a rethinking of the evolutionary role of plasticity.},
}
@article {pmid24091924,
year = {2013},
author = {VanderLaan, DP and Ren, Z and Vasey, PL},
title = {Male androphilia in the ancestral environment. An ethnological analysis.},
journal = {Human nature (Hawthorne, N.Y.)},
volume = {24},
number = {4},
pages = {375-401},
doi = {10.1007/s12110-013-9182-z},
pmid = {24091924},
issn = {1936-4776},
mesh = {*Altruism ; Family ; Homosexuality, Male/ethnology ; Humans ; Male ; Men/*psychology ; Sexual Behavior/*ethnology ; Transgender Persons/psychology ; },
abstract = {The kin selection hypothesis posits that male androphilia (male sexual attraction to adult males) evolved because androphilic males invest more in kin, thereby enhancing inclusive fitness. Increased kin-directed altruism has been repeatedly documented among a population of transgendered androphilic males, but never among androphilic males in other cultures who adopt gender identities as men. Thus, the kin selection hypothesis may be viable if male androphilia was expressed in the transgendered form in the ancestral past. Using the Standard Cross-Cultural Sample (SCCS), we examined 46 societies in which male androphilia was expressed in the transgendered form (transgendered societies) and 146 comparison societies (non-transgendered societies). We analyzed SCCS variables pertaining to ancestral sociocultural conditions, access to kin, and societal reactions to homosexuality. Our results show that ancestral sociocultural conditions and bilateral and double descent systems were more common in transgendered than in non-transgendered societies. Across the entire sample, descent systems and residence patterns that would presumably facilitate increased access to kin were associated with the presence of ancestral sociocultural conditions. Among transgendered societies, negative societal attitudes toward homosexuality were unlikely. We conclude that the ancestral human sociocultural environment was likely conducive to the expression of the transgendered form of male androphilia. Descent systems, residence patterns, and societal reactions to homosexuality likely facilitated investments in kin by transgendered males. Given that contemporary transgendered male androphiles appear to exhibit elevated kin-directed altruism, these findings further indicate the viability of the kin selection hypothesis.},
}
@article {pmid24089101,
year = {2013},
author = {Doncaster, CP and Jackson, A and Watson, RA},
title = {Competitive environments sustain costly altruism with negligible assortment of interactions.},
journal = {Scientific reports},
volume = {3},
number = {},
pages = {2836},
doi = {10.1038/srep02836},
pmid = {24089101},
issn = {2045-2322},
mesh = {Adaptation, Biological ; *Altruism ; Animals ; *Biological Evolution ; Computer Simulation ; *Ecosystem ; Models, Theoretical ; *Population Dynamics ; *Selection, Genetic ; },
abstract = {Competition hinders the evolution of altruism amongst kin when beneficiaries gain at the expense of competing relatives. Altruism is consequently deemed to require stronger kin selection, or trait-selected synergies, or elastic population regulation, to counter this effect. Here we contest the view that competition puts any such demands on altruism. In ecologically realistic scenarios, competition influences both altruism and defection. We show how environments that pit defectors against each other allow strong altruism to evolve even in populations with negligible kin structure and no synergies. Competition amongst defectors presents relative advantages to altruism in the simplest games between altruists and defectors, and the most generic models of altruistic phenotypes or genotypes invading non-altruistic populations under inelastic density regulation. Given the widespread inevitability of competition, selection will often favour altruism because its alternatives provide lower fitness. Strong competition amongst defectors nevertheless undermines altruism, by facilitating invasion of unrelated beneficiaries as parasites.},
}
@article {pmid24088564,
year = {2013},
author = {Port, M and Cant, MA},
title = {Longevity suppresses conflict in animal societies.},
journal = {Biology letters},
volume = {9},
number = {5},
pages = {20130680},
doi = {10.1098/rsbl.2013.0680},
pmid = {24088564},
issn = {1744-957X},
mesh = {Animals ; Computer Simulation ; *Conflict (Psychology) ; Cooperative Behavior ; Genetic Fitness/*physiology ; Longevity/*physiology ; *Models, Biological ; Mortality ; Selection, Genetic/physiology ; *Social Behavior ; },
abstract = {Models of social conflict in animal societies generally assume that within-group conflict reduces the value of a communal resource. For many animals, however, the primary cost of conflict is increased mortality. We develop a simple inclusive fitness model of social conflict that takes this cost into account. We show that longevity substantially reduces the level of within-group conflict, which can lead to the evolution of peaceful animal societies if relatedness among group members is high. By contrast, peaceful outcomes are never possible in models where the primary cost of social conflict is resource depletion. Incorporating mortality costs into models of social conflict can explain why many animal societies are so remarkably peaceful despite great potential for conflict.},
}
@article {pmid24047091,
year = {2013},
author = {Saad, G},
title = {The consuming instinct. What Darwinian consumption reveals about human nature.},
journal = {Politics and the life sciences : the journal of the Association for Politics and the Life Sciences},
volume = {32},
number = {1},
pages = {58-72},
doi = {10.2990/32_1_58},
pmid = {24047091},
issn = {1471-5457},
mesh = {*Biological Evolution ; Consumer Behavior ; Female ; *Human Characteristics ; Humans ; Male ; *Psychological Theory ; Selection, Genetic ; Sexual Behavior ; },
abstract = {Editor's note: In this engaging talk given last February on a particularly cold and blustery day at Texas Tech University, Professor Gad Saad of Concordia University discusses his work in the area of evolutionary consumption. In making the case for understanding consumerism from a Darwinian perspective, Saad addresses several key tenets from his books The Consuming Instinct (1) and The Evolutionary Bases of Consumption. (2) In particular, Saad argues that: (1) many consumption acts can be mapped onto four key Darwinian modules (survival, mating, kin selection, and reciprocal altruism); and, (2) cultural products such as song lyrics and movie plotlines are fossils of the human mind that highlight a shared, biologically based human nature. In this wide-ranging inquiry, Saad summarizes several of his other empirical works, including the effects of conspicuous consumption on men's testosterone levels (3) and how the ovulatory cycle in the human female influences consumption. (4) Overall, Professor Saad contends that an infusion of evolutionary and biologically based perspectives into the discipline of consumer behavior and related government regulatory policies yields myriad benefits, notably greater consilience, more effective practices, an ethos of interdisciplinarity, and methodological pluralism.},
}
@article {pmid24033543,
year = {2013},
author = {Preston, SA and Briskie, JV and Burke, T and Hatchwell, BJ},
title = {Genetic analysis reveals diverse kin-directed routes to helping in the rifleman Acanthisitta chloris.},
journal = {Molecular ecology},
volume = {22},
number = {19},
pages = {5027-5039},
doi = {10.1111/mec.12448},
pmid = {24033543},
issn = {1365-294X},
mesh = {Animals ; Female ; *Genetic Fitness ; Genotype ; *Helping Behavior ; Male ; Microsatellite Repeats ; New Zealand ; Passeriformes/*genetics ; Reproduction/genetics ; *Sexual Behavior, Animal ; },
abstract = {The social organization of cooperatively breeding species is extremely variable, with diverse social group composition and patterns of relatedness. Species that exhibit alternative routes to helping within the same population are potentially useful systems to investigate the causes and fitness consequences of diverse evolutionary pathways to cooperative behaviour. In this study, we use microsatellite markers and field observations to describe helping behaviour and patterns of relatedness in the unusual cooperative breeding system of the rifleman Acanthisitta chloris. First, we show that rifleman helpers consist of a remarkably diverse demographic, including males and females, who may be adult or juvenile, failed breeders or nonbreeders, or even successful breeders that simultaneously feed their own brood. Adult helpers mostly helped at first-brood nests, while first-brood juveniles assisted their parents at second broods. Second, we show that rifleman pairs are strictly sexually monogamous, and helpers did not gain any current reproductive success through helping. Third, genotyping showed that contrary to previous assumptions, helpers were closely related to the recipients of their care and preferentially directed care towards relatives over contemporaneous nests of nonrelatives. Finally, we show that variation in helper provisioning effort was attributed to age: juvenile helpers provisioned less than adults and were less responsive to the demands of a growing brood. Overall, our results show that the diverse routes to helping in this unusual species are driven by the common theme of kinship between helper and recipients, resulting in a previously underestimated potential for helpers to gain indirect fitness benefits.},
}
@article {pmid24028471,
year = {2013},
author = {Lion, S},
title = {Multiple infections, kin selection and the evolutionary epidemiology of parasite traits.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {10},
pages = {2107-2122},
doi = {10.1111/jeb.12207},
pmid = {24028471},
issn = {1420-9101},
mesh = {Animals ; *Biological Evolution ; Coinfection/*parasitology ; *Host-Parasite Interactions ; *Models, Biological ; Parasites/*pathogenicity/physiology ; Virulence ; },
abstract = {The coinfection of a host by several parasite strains is known to affect selective pressures on parasite strategies of host exploitation. I present a general model of coinfections that ties together kin selection models of virulence evolution and epidemiological models of multiple infections. I derive an analytical expression for the invasion fitness of a rare mutant in a population with an arbitrary distribution of the multiplicity of infection (MOI) across hosts. When a single mutation affects parasite strategies in all MOI classes, I show that the evolutionarily stable level of virulence depends on a demographic average of within-host relatedness across all host classes. This generalization of previous kin selection results requires that within-host parasite densities do not vary between hosts. When host exploitation strategies are allowed to vary across classes, I show that the strategy of host exploitation in a focal MOI class depends on the relative magnitudes of parasite reproductive values in the focal class and in the next. Thus, in contrast to previous findings, lower within-host relatedness in competitive parasite interactions can potentially correspond to either higher or lower levels of virulence.},
}
@article {pmid24004898,
year = {2013},
author = {Moore, D and Wigby, S and English, S and Wong, S and Székely, T and Harrison, F},
title = {Selflessness is sexy: reported helping behaviour increases desirability of men and women as long-term sexual partners.},
journal = {BMC evolutionary biology},
volume = {13},
number = {},
pages = {182},
doi = {10.1186/1471-2148-13-182},
pmid = {24004898},
issn = {1471-2148},
mesh = {Adult ; Altruism ; *Biological Evolution ; Choice Behavior ; Female ; *Helping Behavior ; Humans ; Male ; *Marriage ; Young Adult ; },
abstract = {BACKGROUND: Despite its short-term costs, behaviour that appears altruistic can increase an individual's inclusive fitness by earning direct (selfish) and/or indirect (kin-selected) benefits. An evolved preference for other-regarding or helping behaviour in potential mates has been proposed as an additional mechanism by which these behaviours can yield direct fitness benefits in humans.

RESULTS: We asked 32 heterosexual women and 35 heterosexual men to rate the attractiveness of members of the opposite sex in the presence and the absence of information about helping behaviours. Reports of helping behaviour were associated with a significant increase in the attractiveness of both men and women as potential long-term sexual partners. Altruism also increased the attractiveness of men as potential partners for short-term flings, but to a lesser extent than when the same men were being considered for long-term relationships. Altruism did not affect the attractiveness of women as partners for short-term flings.

CONCLUSIONS: Our results unite two important areas of evolutionary theory - social evolution and sexual selection - and extend the list of means by which helping behaviours, which appear at first glance to be costly to the actor, can in fact earn direct fitness benefits. Helping behaviours may be attractive because they signal 'good genes' and/or because they are perceived as a signal of likely provision of non-genetic benefits (e.g. parental care). Exactly why helping behaviours in a non-mating context might be attractive to potential mates, and whether they are honest signals of mate quality, remains to be elucidated.},
}
@article {pmid23945693,
year = {2013},
author = {Jaeggi, AV and Gurven, M},
title = {Reciprocity explains food sharing in humans and other primates independent of kin selection and tolerated scrounging: a phylogenetic meta-analysis.},
journal = {Proceedings. Biological sciences},
volume = {280},
number = {1768},
pages = {20131615},
doi = {10.1098/rspb.2013.1615},
pmid = {23945693},
issn = {1471-2954},
mesh = {Animals ; *Cooperative Behavior ; *Helping Behavior ; Humans ; Phylogeny ; Primates/*psychology ; Species Specificity ; },
abstract = {Helping, i.e. behaviour increasing the fitness of others, can evolve when directed towards kin or reciprocating partners. These predictions have been tested in the context of food sharing both in human foragers and non-human primates. Here, we performed quantitative meta-analyses on 32 independent study populations to (i) test for overall effects of reciprocity on food sharing while controlling for alternative explanations, methodological biases, publication bias and phylogeny and (ii) compare the relative effects of reciprocity, kinship and tolerated scrounging, i.e. sharing owing to costs imposed by others. We found a significant overall weighted effect size for reciprocity of r = 0.20-0.48 for the most and least conservative measure, respectively. Effect sizes did not differ between humans and other primates, although there were species differences in in-kind reciprocity and trade. The relative effect of reciprocity in sharing was similar to those of kinship and tolerated scrounging. These results indicate a significant independent contribution of reciprocity to human and primate helping behaviour. Furthermore, similar effect sizes in humans and primates speak against cognitive constraints on reciprocity. This study is the first to use meta-analyses to quantify these effects on human helping and to directly compare humans and other primates.},
}
@article {pmid23910660,
year = {2013},
author = {Naeger, NL and Peso, M and Even, N and Barron, AB and Robinson, GE},
title = {Altruistic behavior by egg-laying worker honeybees.},
journal = {Current biology : CB},
volume = {23},
number = {16},
pages = {1574-1578},
doi = {10.1016/j.cub.2013.06.045},
pmid = {23910660},
issn = {1879-0445},
support = {1DP10D006416/DP/NCCDPHP CDC HHS/United States ; },
mesh = {Altruism ; Animals ; Bees/genetics/*physiology ; Female ; *Nesting Behavior ; New South Wales ; Reproduction ; Selection, Genetic ; Social Behavior ; },
abstract = {If a honeybee (Apis mellifera) colony loses its queen, worker bees develop their ovaries and produce male offspring [1]. Kin selection theory predicts that the degree of altruism in queenless colonies should be reduced because the relatedness of workers to a hivemate's offspring is less in queenless colonies than it is to the daughters of the queen in queenright colonies [2-4]. To explore this hypothesis, we examined the behavior and physiology of queenless egg-laying workers. Queenless bees engaged in both personal reproduction and the social foraging and defense tasks that benefited their colony. Laying workers also had larger brood-food-producing and wax glands, showing metabolic investments in both colony maintenance and personal reproduction. Whereas in queenright colonies there is a very clear age-based pattern of division of labor between workers, in queenless colonies the degree of individual specialization was much reduced. Queenless colonies functioned as a collective of reproductive and behaviorally generalist bees that cooperatively maintained and defended their nest. This social structure is similar to that observed in a number of primitively social bee species [5]. Laying workers therefore show a mix of selfish personal reproduction and altruistic cooperative behavior, and the queenless state reveals previously unrecognized plasticity in honeybee social organization.},
}
@article {pmid23895053,
year = {2013},
author = {Satow, S and Satoh, T and Hirota, T},
title = {Colony fusion in a parthenogenetic ant, Pristomyrmex punctatus.},
journal = {Journal of insect science (Online)},
volume = {13},
number = {},
pages = {38},
doi = {10.1673/031.013.3801},
pmid = {23895053},
issn = {1536-2442},
mesh = {*Aggression ; Animals ; *Ants ; Competitive Behavior ; Female ; *Nesting Behavior ; Parthenogenesis ; },
abstract = {In the ant Pristomyrmex punctatus Smith (Hymenoptera: Formicidae), all young workers lay a small number of eggs parthenogenetically. Some colonies consist of monoclonal individuals that provide high inclusive fitness, according to the kin selection theory. However, in some populations, a majority of the colonies contain multiple lineages. Intracolonial genetic variation of parthenogenetic ants cannot be explained by the multiple mating of single founderesses or by the foundation of a colony by multiple foundresses, which are the usual causes of genetically diverse colonies in social insects. Here, we hypothesized that the fusion of established colonies might facilitate the formation of multiclonal colonies. Colony fusion decreases indirect benefits because of the reduction in intracolonial relatedness. However, when suitable nesting places for overwintering are scarce, colony fusion provides a strategy for the survival of colonies. Here, ants derived from different colonies were allowed to encounter one another in a container with just one nesting place. Initially, high aggression was observed; however, after several days, no aggression was observed and the ants shared the nest. When the fused colonies were allowed to transfer to two alternative nests, ants from different colonies occupied the same nest. This study highlights the importance of limiting the number of nesting places in order to understand the genetic diversity of parthenogenetic ant colonies.},
}
@article {pmid23889604,
year = {2013},
author = {Holmes, MJ and Oldroyd, BP and Duncan, M and Allsopp, MH and Beekman, M},
title = {Cheaters sometimes prosper: targeted worker reproduction in honeybee (Apis mellifera) colonies during swarming.},
journal = {Molecular ecology},
volume = {22},
number = {16},
pages = {4298-4306},
doi = {10.1111/mec.12387},
pmid = {23889604},
issn = {1365-294X},
mesh = {Animals ; Bees/*genetics/*physiology ; Female ; Genotype ; Male ; Pupa/genetics ; *Reproduction/genetics/physiology ; Sexual Behavior, Animal/*physiology ; Social Behavior ; },
abstract = {Kin selection theory predicts that honeybee (Apis mellifera) workers should largely refrain from producing their own offspring, as the workers collectively have higher inclusive fitness if they rear the sons of their mother, the queen. Studies that have quantified levels of ovary activation and reproduction among workers have largely supported this prediction. We sampled pre-emergent male pupae and adult workers from seven colonies at regular intervals throughout the reproductive part of the season. We show that the overall contribution of workers to male (drone) production is 4.2%, nearly 40 times higher than is generally reported, and is highest during reproductive swarming, when an average of 6.2% of the males genotyped are worker-produced. Similarly, workers in our samples were 100 times more likely to have active ovaries than previously assumed. Worker reproduction is seasonally influenced and peaks when colonies are rearing new queens. Not all worker subfamilies contribute equally to reproduction. Instead, certain subfamilies are massively over-represented in drone brood. By laying eggs within the period in which many colonies produce virgin queens, these rare worker subfamilies increase their direct fitness via their well-timed sons.},
}
@article {pmid23888851,
year = {2013},
author = {Rodrigues, AM and Gardner, A},
title = {Evolution of helping and harming in heterogeneous groups.},
journal = {Evolution; international journal of organic evolution},
volume = {67},
number = {8},
pages = {2284-2298},
doi = {10.1111/evo.12110},
pmid = {23888851},
issn = {1558-5646},
mesh = {Amoeba/genetics/physiology ; Animals ; *Biological Evolution ; Helping Behavior ; Models, Biological ; *Social Behavior ; Wasps/genetics/physiology ; },
abstract = {Social groups are often composed of individuals who differ in many respects. Theoretical studies on the evolution of helping and harming behaviors have largely focused upon genetic differences between individuals. However, nongenetic variation between group members is widespread in natural populations, and may mediate differences in individuals' social behavior. Here, we develop a framework to study how variation in individual quality mediates the evolution of unconditional and conditional social traits. We investigate the scope for the evolution of social traits that are conditional on the quality of the actor and/or recipients. We find that asymmetries in individual quality can lead to the evolution of plastic traits with different individuals expressing helping and harming traits within the same group. In this context, population viscosity can mediate the evolution of social traits, and local competition can promote both helping and harming behaviors. Furthermore, asymmetries in individual quality can lead to the evolution of competition-like traits between clonal individuals. Overall, we highlight the importance of asymmetries in individual quality, including differences in reproductive value and the ability to engage in successful social interactions, in mediating the evolution of helping and harming behaviors.},
}
@article {pmid23856025,
year = {2013},
author = {Rand, DG and Nowak, MA},
title = {Human cooperation.},
journal = {Trends in cognitive sciences},
volume = {17},
number = {8},
pages = {413-425},
doi = {10.1016/j.tics.2013.06.003},
pmid = {23856025},
issn = {1879-307X},
mesh = {Choice Behavior ; *Cooperative Behavior ; Humans ; Interpersonal Relations ; *Models, Psychological ; },
abstract = {Why should you help a competitor? Why should you contribute to the public good if free riders reap the benefits of your generosity? Cooperation in a competitive world is a conundrum. Natural selection opposes the evolution of cooperation unless specific mechanisms are at work. Five such mechanisms have been proposed: direct reciprocity, indirect reciprocity, spatial selection, multilevel selection, and kin selection. Here we discuss empirical evidence from laboratory experiments and field studies of human interactions for each mechanism. We also consider cooperation in one-shot, anonymous interactions for which no mechanisms are apparent. We argue that this behavior reflects the overgeneralization of cooperative strategies learned in the context of direct and indirect reciprocity: we show that automatic, intuitive responses favor cooperative strategies that reciprocate.},
}
@article {pmid23852350,
year = {2013},
author = {Ratcliff, WC and Hoverman, M and Travisano, M and Denison, RF},
title = {Disentangling direct and indirect fitness effects of microbial dormancy.},
journal = {The American naturalist},
volume = {182},
number = {2},
pages = {147-156},
doi = {10.1086/670943},
pmid = {23852350},
issn = {1537-5323},
mesh = {*Biological Evolution ; *Models, Biological ; Saccharomyces cerevisiae/*physiology ; *Selection, Genetic ; },
abstract = {Disentangling individual selection from kin selection is one of the greatest challenges of evolutionary biology. Even solitary organisms that do not interact directly with conspecifics may interact indirectly with them through competition for resources. As a result, traits that appear to affect individual fitness alone can also modify the fitness of relatives nearby and thus may evolve partially through these cryptic indirect fitness effects. Here we develop a method to quantitatively separate direct and indirect fitness consequences when some microbes become dormant, while neighbors of the same genotype remain active. Dormant microbes typically survive stresses that kill metabolically active cells, but dormancy also has a social side effect, sparing resources that may be used by nondormant individuals for growth. In structured populations, spared resources may be preferentially consumed by nondormant clonemates, providing an indirect benefit. Without population structure, however, exploitation by a never-dormant competitor imposes an indirect fitness cost on dormant cells. Cryptic indirect fitness effects may play a significant role in the evolution of many ostensibly asocial traits.},
}
@article {pmid23848984,
year = {2013},
author = {Alizon, S},
title = {On the limits of interpreting some plastic responses through a cooperator/cheater prism. A comment on Harrison.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {9},
pages = {2051-2056},
doi = {10.1111/jeb.12199},
pmid = {23848984},
issn = {1420-9101},
mesh = {Pseudomonas aeruginosa/*physiology ; Siderophores/*metabolism ; },
abstract = {Micro-organisms are known to exhibit phenotypic plasticity in response to changes in their environment. Recent studies have shown that a parasite strain can adjust its host exploitation strategies to the presence of unrelated strains, e.g. for Plasmodium chabaudi by adjusting its sex-ratio. J. Evol. Biol. 2013; 26: 1370-1378 claims to report a similar plastic response to the presence of unrelated strains in the case of siderophore-producing bacteria. I argue that she does not provide sufficient evidence to support the interpretation of the plastic response she observes (increasing siderophore production in the presence of cheaters) through a cooperator/cheater framework. I show that known plastic responses to physicochemical factors, such as siderophore or iron concentration, seem to offer a clearer and more parsimonious explanation. Finally, I also challenge the parallel she makes between the process she observes in siderophore-producing bacteria and compensation in bi-parental care models.},
}
@article {pmid23848844,
year = {2013},
author = {Wyatt, GA and West, SA and Gardner, A},
title = {Can natural selection favour altruism between species?.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {9},
pages = {1854-1865},
doi = {10.1111/jeb.12195},
pmid = {23848844},
issn = {1420-9101},
support = {//Biotechnology and Biological Sciences Research Council/United Kingdom ; },
mesh = {*Altruism ; *Biological Evolution ; Genetic Fitness/*genetics ; *Genetics, Population ; Linear Models ; *Models, Genetic ; *Selection, Genetic ; Species Specificity ; },
abstract = {Darwin suggested that the discovery of altruism between species would annihilate his theory of natural selection. However, it has not been formally shown whether between-species altruism can evolve by natural selection, or why this could never happen. Here, we develop a spatial population genetic model of two interacting species, showing that indiscriminate between species helping can be favoured by natural selection. We then ask if this helping behaviour constitutes altruism between species, using a linear-regression analysis to separate the total action of natural selection into its direct and indirect (kin selected) components. We show that our model can be interpreted in two ways, as either altruism within species, or altruism between species. This ambiguity arises depending on whether or not we treat genes in the other species as predictors of an individual's fitness, which is equivalent to treating these individuals as agents (actors or recipients). Our formal analysis, which focuses upon evolutionary dynamics rather than agents and their agendas, cannot resolve which is the better approach. Nonetheless, because a within-species altruism interpretation is always possible, our analysis supports Darwin's suggestion that natural selection does not favour traits that provide benefits exclusively to individuals of other species.},
}
@article {pmid23845249,
year = {2013},
author = {West, SA and Gardner, A},
title = {Adaptation and inclusive fitness.},
journal = {Current biology : CB},
volume = {23},
number = {13},
pages = {R577-84},
doi = {10.1016/j.cub.2013.05.031},
pmid = {23845249},
issn = {1879-0445},
mesh = {*Adaptation, Biological ; Biological Evolution ; *Genetic Fitness ; Genome ; Humans ; Phenotype ; Reproduction ; *Selection, Genetic ; },
abstract = {Inclusive fitness theory captures how individuals can influence the transmission of their genes to future generations by influencing either their own reproductive success or that of related individuals. This framework is frequently used for studying the way in which natural selection leads to organisms being adapted to their environments. A number of recent papers have criticised this approach, suggesting that inclusive fitness is just one of many possible mathematical methods for modelling when traits will be favoured by natural selection, and that it leads to errors, such as overemphasising the role of common ancestry relative to other mechanisms that could lead to individuals being genetically related. Here, we argue that these suggested problems arise from a misunderstanding of two fundamental points: first, inclusive fitness is more than just a mathematical 'accounting method' - it is the answer to the question of what organisms should appear designed to maximise; second, there is something special about relatedness caused by common ancestry, in contrast with the other mechanisms that may lead to individuals being genetically related, because it unites the interests of genes across the genome, allowing complex, multigenic adaptations to evolve. The critiques of inclusive fitness theory have provided neither an equally valid answer to the question of what organisms should appear designed to maximise, nor an alternative process to unite the interest of genes. Consequently, inclusive fitness remains the most general theory for explaining adaptation.},
}
@article {pmid23825662,
year = {2013},
author = {Chong, G and Kimyon, O and Manefield, M},
title = {Quorum Sensing Signal Synthesis May Represent a Selective Advantage Independent of Its Role in Regulation of Bioluminescence in Vibrio fischeri.},
journal = {PloS one},
volume = {8},
number = {6},
pages = {e67443},
doi = {10.1371/journal.pone.0067443},
pmid = {23825662},
issn = {1932-6203},
mesh = {Aliivibrio fischeri/*physiology ; *Luminescence ; Quorum Sensing ; },
abstract = {The evolution of biological signalling systems and apparently altruistic or cooperative traits in diverse organisms has required selection against the subversive tendencies of self-interested biological entities. The bacterial signalling and response system known as quorum sensing or Acylated Homoserine Lactone (AHL) mediated gene expression is thought to have evolved through kin selection. In this in vitro study on the model quorum sensing bioluminescent marine symbiont Vibrio fischeri, competition and long-term sub culturing experiments suggest that selection for AHL synthesis (encoded by the AHL synthase gene luxI) is independent of the quorum sensing regulated phenotype (bioluminescence encoded by luxCDABE). Whilst results support the hypothesis that signal response (AHL binding and transcriptional activation encoded by the luxR gene) is maintained through indirect fitness benefits (kin selection), signal synthesis is maintained in the V. fischeri genome over evolutionary time through direct fitness benefits at the individual level from an unknown function.},
}
@article {pmid23817946,
year = {2013},
author = {Morelli, TL and Hayes, RA and Nahrung, HF and Goodwin, TE and Harelimana, IH and Macdonald, LJ and Wright, PC},
title = {Relatedness communicated in lemur scent.},
journal = {Die Naturwissenschaften},
volume = {100},
number = {8},
pages = {769-777},
doi = {10.1007/s00114-013-1074-x},
pmid = {23817946},
issn = {1432-1904},
mesh = {*Animal Communication ; Animals ; Female ; Gas Chromatography-Mass Spectrometry ; Lemur/genetics/*physiology ; Madagascar ; Male ; Multivariate Analysis ; Pheromones/*chemistry/genetics ; Scent Glands/chemistry ; },
abstract = {Lemurs are the most olfactory-oriented of primates, yet there is still only a basic level of understanding of what their scent marks communicate. We analyzed scent secretions from Milne-Edwards' sifakas (Propithecus edwardsi) collected in their natural habitat of Ranomafana National Park, Madagascar. We sought to test whether the scent mark could signal genetic relatedness in addition to species, sex, season, and individuality. We not only found correlations (r (2) = 0.38, P = 0.017) between the total olfactory fingerprint and genetic relatedness but also between relatedness and specific components of the odor, despite the complex environmental signals from differences in diet and behavior in a natural setting. To the best of our knowledge, this is the first demonstration of an association between genetic relatedness and chemical communication in a wild primate population. Furthermore, we found a variety of compounds that were specific to each sex and each sampling period. This research shows that scent marks could act as a remote signal to avoid inbreeding, optimize mating opportunities, and potentially aid kin selection.},
}
@article {pmid23807025,
year = {2013},
author = {Kobayashi, K and Hasegawa, E and Yamamoto, Y and Kawatsu, K and Vargo, EL and Yoshimura, J and Matsuura, K},
title = {Sex ratio biases in termites provide evidence for kin selection.},
journal = {Nature communications},
volume = {4},
number = {},
pages = {2048},
doi = {10.1038/ncomms3048},
pmid = {23807025},
issn = {2041-1723},
mesh = {Animals ; Female ; Hierarchy, Social ; Inbreeding ; Isoptera/growth & development/*physiology ; Life Cycle Stages ; Male ; Models, Biological ; Reproduction, Asexual/physiology ; *Selection, Genetic ; *Sex Ratio ; *Sexism ; Social Behavior ; },
abstract = {Inclusive fitness theory, also known as kin selection theory, is the most general expansion of Darwin's natural selection theory. It is supported by female-biased investment by workers in the social Hymenoptera where relatedness to sisters is higher than to brothers because of haplodiploidy. However, a strong test of the theory has proven difficult in diploid social insects because they lack such relatedness asymmetry. Here we show that kin selection can result in sex ratio bias in eusocial diploids. Our model predicts that allocation will be biased towards the sex that contributes more of its genes to the next generation when sex-asymmetric inbreeding occurs. The prediction matches well with the empirical sex allocation of Reticulitermes termites where the colony king can be replaced by a queen's son. Our findings open broad new avenues to test inclusive fitness theory beyond the well-studied eusocial Hymenoptera.},
}
@article {pmid23805291,
year = {2013},
author = {Brante, A and Fernández, M and Viard, F},
title = {Non-Random Sibling Cannibalism in the Marine Gastropod Crepidula coquimbensis.},
journal = {PloS one},
volume = {8},
number = {6},
pages = {e67050},
doi = {10.1371/journal.pone.0067050},
pmid = {23805291},
issn = {1932-6203},
mesh = {Animals ; Behavior, Animal/physiology ; *Cannibalism ; DNA/isolation & purification/metabolism ; Female ; Gastropoda/genetics/*physiology ; Genotype ; Male ; Microsatellite Repeats ; Siblings ; },
abstract = {Sibling cannibalism is commonly observed in marine species. For instance, intrabrood cannibalism has been documented in marine gastropods with direct development, suggesting a relationship between embryo behavior and the evolution of life history strategies. However, there has been little effort to document the factors driving sibling cannibalism in marine species. The kin selection theory suggests that the level of relatedness plays an important role in cannibalism patterns. We examined Crepidula coquimbensis, a marine gastropod that broods and encloses its brooded offspring in capsules. Encapsulated embryos show sibling cannibalism and high levels of intracapsular multiple paternity. Given these features, cannibalistic behavior may be driven by kin-relatedness. To test this hypothesis, we constructed artificial aggregations of embryos to mimic three levels of relatedness: high, medium and low. For each category of aggregation, the cannibalism rate and benefits (i.e. size at hatching of surviving offspring) were estimated. In addition, at the end of embryo development, we performed parentage analyses to determine if cannibalism was associated with the relatedness between cannibal and victim embryos. Our results show that the intensity of sibling cannibalism increased in aggregations characterized by the lowest level of relatedness. There were important benefits of cannibalism in terms of hatching cannibal size. In addition, cannibalism between embryos was not random: the variation in reproductive success between males increased over the course of the experiment and the effective number of fathers decreased. Altogether, these results suggest that polyandry may play an important role in the evolution of sibling cannibalism in C. coquimbensis and that kin selection may operate during early embryonic stages in this species.},
}
@article {pmid23785268,
year = {2013},
author = {Morton, RA and Stone, JR and Singh, RS},
title = {Mate choice and the origin of menopause.},
journal = {PLoS computational biology},
volume = {9},
number = {6},
pages = {e1003092},
doi = {10.1371/journal.pcbi.1003092},
pmid = {23785268},
issn = {1553-7358},
mesh = {Female ; Humans ; Male ; *Menopause/genetics ; Mutation ; *Sexual Behavior ; },
abstract = {Human menopause is an unsolved evolutionary puzzle, and relationships among the factors that produced it remain understood poorly. Classic theory, involving a one-sex (female) model of human demography, suggests that genes imparting deleterious effects on post-reproductive survival will accumulate. Thus, a 'death barrier' should emerge beyond the maximum age for female reproduction. Under this scenario, few women would experience menopause (decreased fertility with continued survival) because few would survive much longer than they reproduced. However, no death barrier is observed in human populations. Subsequent theoretical research has shown that two-sex models, including male fertility at older ages, avoid the death barrier. Here we use a stochastic, two-sex computational model implemented by computer simulation to show how male mating preference for younger females could lead to the accumulation of mutations deleterious to female fertility and thus produce a menopausal period. Our model requires neither the initial assumption of a decline in older female fertility nor the effects of inclusive fitness through which older, non-reproducing women assist in the reproductive efforts of younger women. Our model helps to explain why such effects, observed in many societies, may be insufficient factors in elucidating the origin of menopause.},
}
@article {pmid23769953,
year = {2013},
author = {Baron, C},
title = {The handicap principle and the argument of subversion from within.},
journal = {Studies in history and philosophy of biological and biomedical sciences},
volume = {44},
number = {3},
pages = {347-355},
doi = {10.1016/j.shpsc.2013.05.001},
pmid = {23769953},
issn = {1879-2499},
mesh = {*Altruism ; *Biological Evolution ; Humans ; *Selection, Genetic ; },
abstract = {This paper examines the very disparate positions that various actors have taken towards the argument of subversion from within (a classical argument against the evolution of altruism by group selection) in a set of related debates on group selection, altruism and the handicap principle. Using this set of debates as a case study, this paper argues that different applications of epistemic values were one of the factors behind the disagreements between John Maynard Smith and Amotz Zahavi over a number of important evolutionary issues. The paper also argues that these different applications were connected to important epistemological differences related in part (but not solely) to their disciplinary background. Apart from conflicting evolutionary views concerning the theoretical feasibility of the handicap effect, these antagonists both differed in the confidence they ascribed to mathematical modeling and over the hereditary basis for altruistic behavior.},
}
@article {pmid23760639,
year = {2013},
author = {Mc Ginty, SÉ and Lehmann, L and Brown, SP and Rankin, DJ},
title = {The interplay between relatedness and horizontal gene transfer drives the evolution of plasmid-carried public goods.},
journal = {Proceedings. Biological sciences},
volume = {280},
number = {1761},
pages = {20130400},
doi = {10.1098/rspb.2013.0400},
pmid = {23760639},
issn = {1471-2954},
support = {095831//Wellcome Trust/United Kingdom ; //Wellcome Trust/United Kingdom ; },
mesh = {Bacteria/*genetics/pathogenicity ; *Biological Evolution ; *Gene Transfer, Horizontal ; Genetics, Population ; Host-Pathogen Interactions/genetics ; *Models, Genetic ; Plasmids/*genetics ; Selection, Genetic ; Virulence Factors/genetics ; },
abstract = {Plasmids carry a wide range of genes that are often involved in bacterial social behaviour. The question of why such genes are frequently mobile has received increasing attention. Here, we use an explicit population genetic approach to model the evolution of plasmid-borne bacterial public goods production. Our findings highlight the importance of both transmission and relatedness as factors driving the evolution of plasmid-borne public goods production. We partition the effects of plasmid transfer of social traits into those of infectivity and the effect of increased relatedness. Our results demonstrate that, owing to its effect on relatedness, plasmid mobility increases the invasion and stability of public goods, in a way not seen in individually beneficial traits. In addition, we show that plasmid transfer increases relatedness when public goods production is rare but this effect declines when production is common, with both scenarios leading to an increase in the frequency of plasmid-borne public goods. Plasmids remain important vectors for the spread of social genes involved in bacterial virulence thus an understanding of their dynamics is highly relevant from a public health perspective.},
}
@article {pmid23730751,
year = {2013},
author = {Simon, B and Fletcher, JA and Doebeli, M},
title = {Towards a general theory of group selection.},
journal = {Evolution; international journal of organic evolution},
volume = {67},
number = {6},
pages = {1561-1572},
doi = {10.1111/j.1558-5646.2012.01835.x},
pmid = {23730751},
issn = {1558-5646},
mesh = {Animals ; Evolution, Molecular ; Markov Chains ; *Models, Genetic ; Population/genetics ; *Selection, Genetic ; },
abstract = {The longstanding debate about the importance of group (multilevel) selection suffers from a lack of formal models that describe explicit selection events at multiple levels. Here, we describe a general class of models for two-level evolutionary processes which include birth and death events at both levels. The models incorporate the state-dependent rates at which these events occur. The models come in two closely related forms: (1) a continuous-time Markov chain, and (2) a partial differential equation (PDE) derived from (1) by taking a limit. We argue that the mathematical structure of this PDE is the same for all models of two-level population processes, regardless of the kinds of events featured in the model. The mathematical structure of the PDE allows for a simple and unambiguous way to distinguish between individual- and group-level events in any two-level population model. This distinction, in turn, suggests a new and intuitively appealing way to define group selection in terms of the effects of group-level events. We illustrate our theory of group selection by applying it to models of the evolution of cooperation and the evolution of simple multicellular organisms, and then demonstrate that this kind of group selection is not mathematically equivalent to individual-level (kin) selection.},
}
@article {pmid23730749,
year = {2013},
author = {Goodnight, C},
title = {On multilevel selection and kin selection: contextual analysis meets direct fitness.},
journal = {Evolution; international journal of organic evolution},
volume = {67},
number = {6},
pages = {1539-1548},
doi = {10.1111/j.1558-5646.2012.01821.x},
pmid = {23730749},
issn = {1558-5646},
mesh = {Animals ; Evolution, Molecular ; *Genetic Fitness ; *Models, Genetic ; *Selection, Genetic ; },
abstract = {When Hamilton defined the concept of inclusive fitness, he specifically was looking to define the fitness of an individual in terms of that individual's behavior, and the effects of its' behavior on other related individuals. Although an intuitively attractive concept, issues of accounting for fitness, and correctly assigning it to the appropriate individual make this approach difficult to implement. The direct fitness approach has been suggested as a means of modeling kin selection while avoiding these issues. Whereas Hamilton's inclusive fitness approach assigns to the focal individual the fitness effects of its behavior on other related individuals, the direct fitness approach assigns the fitness effects of other actors to the focal individual. Contextual analysis was independently developed as a quantitative genetic approach for measuring multilevel selection in natural populations. Although the direct fitness approach and contextual analysis come from very different traditions, both methods rely on the same underlying equation, with the primary difference between the two approaches being that the direct fitness approach uses fitness optimization modeling, whereas with contextual analysis, the same equation is used to solve for the change in fitness associated with a change in phenotype when the population is away from the optimal phenotype.},
}
@article {pmid23717479,
year = {2013},
author = {Ale, SB and Brown, JS and Sullivan, AT},
title = {Evolution of cooperation: combining kin selection and reciprocal altruism into matrix games with social dilemmas.},
journal = {PloS one},
volume = {8},
number = {5},
pages = {e63761},
doi = {10.1371/journal.pone.0063761},
pmid = {23717479},
issn = {1932-6203},
mesh = {*Altruism ; Animals ; *Biological Evolution ; *Cooperative Behavior ; *Game Theory ; *Interpersonal Relations ; },
abstract = {Darwinian selection should preclude cooperation from evolving; yet cooperation is widespread among organisms. We show how kin selection and reciprocal altruism can promote cooperation in diverse 2×2 matrix games (prisoner's dilemma, snowdrift, and hawk-dove). We visualize kin selection as non-random interactions with like-strategies interacting more than by chance. Reciprocal altruism emerges from iterated games where players have some likelihood of knowing the identity of other players. This perspective allows us to combine kin selection and reciprocal altruism into a general matrix game model. Both mechanisms operating together should influence the evolution of cooperation. In the absence of kin selection, reciprocal altruism may be an evolutionarily stable strategy but is unable to invade a population of non-co-operators. Similarly, it may take a high degree of relatedness to permit cooperation to supplant non-cooperation. Together, a little bit of reciprocal altruism can, however, greatly reduce the threshold at which kin selection promotes cooperation, and vice-versa. To properly frame applications and tests of cooperation, empiricists should consider kin selection and reciprocal altruism together rather than as alternatives, and they should be applied to a broader class of social dilemmas than just the prisoner's dilemma.},
}
@article {pmid23714691,
year = {2013},
author = {Cable, J and Archard, GA and Mohammed, RS and McMullan, M and Stephenson, JF and Hansen, H and van Oosterhout, C},
title = {Can parasites use predators to spread between primary hosts?.},
journal = {Parasitology},
volume = {140},
number = {9},
pages = {1138-1143},
doi = {10.1017/S003118201300067X},
pmid = {23714691},
issn = {1469-8161},
mesh = {Animals ; Ectoparasitic Infestations/parasitology/transmission/*veterinary ; Fish Diseases/parasitology/*transmission ; Host-Parasite Interactions ; Killifishes/*parasitology ; Platyhelminths/*physiology ; Poecilia/*parasitology ; Time Factors ; Trematode Infections/parasitology/transmission/veterinary ; },
abstract = {Parasites typically have low reproductive fitness on paratenic hosts. Such hosts offer other significant inclusive fitness benefits to parasites, however, such as increased mobility and migration potential. The parasite fauna of the guppy (Poecilia reticulata) is dominated by the directly transmitted ectoparasites Gyrodactylus bullatarudis and Gyrodactylus turnbulli. In the wild, close predatory and competitive interactions occur between the guppy and the killifish Rivulus hartii. Previous observations suggest that these fish can share gyrodactylids, so we tested experimentally whether these parasites can use R. hartii as an alternative host. In aquaria, G. bullatarudis was the only species able to transmit from prey to predator. Both parasite species transferred equally well to prey when the predator was experimentally infected. However, in semi-natural conditions, G. bullatarudis transmitted more successfully to the prey fish. Importantly, G. bullatarudis also survived significantly longer on R. hartii out of water. As R. hartii can migrate overland between isolated guppy populations, G. bullatarudis may have an enhanced ability to disperse and colonize new host populations, consistent with its wider distribution in the wild. To our knowledge, this is the first empirical study demonstrating a predator acting as a paratenic host for the parasites of its prey.},
}
@article {pmid23710754,
year = {2013},
author = {Luchetti, A and Dedeine, F and Velonà, A and Mantovani, B},
title = {Extreme genetic mixing within colonies of the wood-dwelling termite Kalotermes flavicollis (Isoptera, Kalotermitidae).},
journal = {Molecular ecology},
volume = {22},
number = {12},
pages = {3391-3402},
doi = {10.1111/mec.12302},
pmid = {23710754},
issn = {1365-294X},
mesh = {Animals ; Cell Nucleus/genetics ; DNA, Mitochondrial/genetics ; Genetic Variation ; Isoptera/*genetics ; Microsatellite Repeats ; Molecular Sequence Data ; Reproduction/genetics ; Sequence Analysis, DNA ; },
abstract = {The existence of altruism in social insects is commonly attributed to altruistic individuals gaining indirect fitness through kin selection. However, recent studies suggest that such individuals might also gain direct fitness through reproduction. Experimental studies on primitive wood-dwelling termites revealed that colony fusion often causes the death of primary reproductives (queen and king), allowing opportunities for workers to inherit the nest by developing into replacement reproductives (neotenics). Therefore, colony fusion has been proposed as an important factor that may have favoured sociality in termites. However, whether colony fusion occurs frequently in natural populations of wood-dwelling termites remains an open question. We analysed eleven colonies of the wood-dwelling termite Kalotermes flavicollis (Kalotermitidae), using two mitochondrial and five nuclear microsatellite markers. Nine of eleven colonies (82%) were mixed families, with offspring of three or more primary reproductives. To our knowledge, this result represents the highest frequency of mixed-family colonies ever reported in termites. Moreover, genetic mixing of colonies appeared extreme in two ways. First, the number of haplotypes per colony was exceptionally high (up to nine), indicating that colonies were composed of multiple queens' offspring. Second, some mixed-family colonies included individuals belonging to two highly divergent genetic lineages. F-statistics and relatedness values suggest that mixed-family colonies most likely result from colony fusion, giving support to the accelerated nest inheritance theory. These findings raise important questions about the mode of foundation of mixed-family colonies and the evolutionary forces that maintain them within populations.},
}
@article {pmid23684769,
year = {2013},
author = {Sozou, PD},
title = {Kin selection and local competition in a heterogeneous community.},
journal = {Journal of theoretical biology},
volume = {332},
number = {},
pages = {261-266},
doi = {10.1016/j.jtbi.2013.05.003},
pmid = {23684769},
issn = {1095-8541},
mesh = {Animals ; *Models, Biological ; *Selection, Genetic ; *Social Behavior ; },
abstract = {When should an individual be willing to pay a cost in order to help or harm another individual in its community? Kin selection suggests that relatives should help each other, while competition for limited resources may select for harming behaviour against neighbours. This study considers social interactions between two individuals. For actions influencing non-dispersing reproduction, a condition is derived for selection to favour helping or harming, as a function of the actor's relationship to the rest of its community and to the recipient. Where two individuals differ in their relatedness to the community, the individual which is less related to the community will be the more helpful. Two individuals with a given relatedness to each other will be more helpful to each other as they jointly become less related to their community. The implications of these results are explored through an example involving a community derived from two ancestral groups. The directional selective effects will depend on the extent to which social interactions are assortative rather than random, and the distribution of opportunities for helping and harming.},
}
@article {pmid23682605,
year = {2013},
author = {Schuster, M and Sexton, DJ and Diggle, SP and Greenberg, EP},
title = {Acyl-homoserine lactone quorum sensing: from evolution to application.},
journal = {Annual review of microbiology},
volume = {67},
number = {},
pages = {43-63},
doi = {10.1146/annurev-micro-092412-155635},
pmid = {23682605},
issn = {1545-3251},
support = {P30 DK089507/DK/NIDDK NIH HHS/United States ; GM-59026/GM/NIGMS NIH HHS/United States ; P30 DK 89507/DK/NIDDK NIH HHS/United States ; },
mesh = {Acyl-Butyrolactones/*metabolism ; Bacteria/genetics ; *Bacterial Physiological Phenomena ; *Biological Evolution ; Industrial Microbiology ; Pseudomonas aeruginosa/genetics/metabolism ; *Quorum Sensing ; },
abstract = {Quorum sensing (QS) is a widespread process in bacteria that employs autoinducing chemical signals to coordinate diverse, often cooperative activities such as bioluminescence, biofilm formation, and exoenzyme secretion. Signaling via acyl-homoserine lactones is the paradigm for QS in Proteobacteria and is particularly well understood in the opportunistic pathogen Pseudomonas aeruginosa. Despite thirty years of mechanistic research, empirical studies have only recently addressed the benefits of QS and provided support for the traditional assumptions regarding its social nature and its role in optimizing cell-density-dependent group behaviors. QS-controlled public-goods production has served to investigate principles that explain the evolution and stability of cooperation, including kin selection, pleiotropic constraints, and metabolic prudence. With respect to medical application, appreciating social dynamics is pertinent to understanding the efficacy of QS-inhibiting drugs and the evolution of resistance. Future work will provide additional insight into the foundational assumptions of QS and relate laboratory discoveries to natural ecosystems.},
}
@article {pmid23682587,
year = {2013},
author = {Langos, D and Kulik, L and Mundry, R and Widdig, A},
title = {The impact of paternity on male-infant association in a primate with low paternity certainty.},
journal = {Molecular ecology},
volume = {22},
number = {13},
pages = {3638-3651},
doi = {10.1111/mec.12328},
pmid = {23682587},
issn = {1365-294X},
support = {P40 OD012217/OD/NIH HHS/United States ; P40 RR003640/RR/NCRR NIH HHS/United States ; 8 P40 OD012217-25/OD/NIH HHS/United States ; },
mesh = {Animals ; Female ; Genotype ; Macaca mulatta/*genetics ; Male ; Paternal Behavior/*physiology ; Puerto Rico ; Reproduction/genetics ; Sexual Behavior, Animal/*physiology ; Sexual Maturation/genetics ; },
abstract = {In multimale groups where females mate promiscuously, male-infant associations have rarely been studied. However, recent studies have shown that males selectively support their offspring during agonistic conflicts with other juveniles and that father's presence accelerates offspring maturation. Furthermore, it was shown that males invest in unrelated infants to enhance future mating success with the infant's mother. Hence, infant care might provide fitness gain for males. Here, we investigate male-infant associations in rhesus macaques (Macaca mulatta), a primate with low paternity certainty as females mate with multiple partners and males ensure paternity less efficiently through mate-guarding. We combined behavioural data with genetic paternity analyses of one cohort of the semi-free-ranging population of Cayo Santiago (Puerto Rico) and recorded affiliative and aggressive interactions between focal subjects and adult males from birth to sexual maturation (0-4 years) of focal subjects. Our results revealed that 9.6% of all interactions of focal subjects involved an adult male and 94% of all male-infant interactions were affiliative, indicating the rareness of male-infant aggression. Second and most interestingly, sires were more likely to affiliate with their offspring than nonsires with unrelated infants. This preference was independent of mother's proximity and emphasized during early infancy. Male-infant affiliation rose with infant age and was pronounced between adult males and male rather than female focal subjects. Overall, our results suggest that male-infant affiliation is also an important component in structuring primate societies and affiliation directed towards own offspring presumably represent low-cost paternal care.},
}
@article {pmid23681276,
year = {2013},
author = {Rimmer, JH and Henley, KY},
title = {Building the crossroad between inpatient/outpatient rehabilitation and lifelong community-based fitness for people with neurologic disability.},
journal = {Journal of neurologic physical therapy : JNPT},
volume = {37},
number = {2},
pages = {72-77},
doi = {10.1097/NPT.0b013e318291bbf6},
pmid = {23681276},
issn = {1557-0584},
mesh = {*Continuity of Patient Care ; *Disabled Persons ; *Health Promotion ; Humans ; Inpatients ; Nervous System Diseases/*rehabilitation ; Outpatients ; *Physical Fitness ; },
abstract = {The length of stay in inpatient and outpatient rehabilitation after an injury or illness has declined in recent years, exposing those with newly acquired neurologic disability to a risk of significant postrehabilitation health decline. Following a short stay in outpatient rehabilitation, individuals with neurologic disability have few, if any, options to continue their physical recovery after discharge, thus further increasing their risk for functional decline and secondary conditions. Professionals who work in community-based fitness facilities have the potential to assist therapists in extending the recovery process and preventing this decline. The focus of this article was to address a conceptual framework for better understanding how rehabilitation and health/fitness professionals can work together to help with this growing need. To that end, the antecedents to and effects of postrehabilitation health decline are discussed, followed by the introduction of a theoretical model illustrating a therapist-to-trainer system that facilitates the use of community-based fitness facilities by individuals with neurologic disabilities to continue their recovery postrehabilitation. Finally, a thorough description of an exemplary existing community-based inclusive fitness program is presented, followed by examples of select disability groups using these programs for continued recovery.Video Abstract available (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A45) for more insights from the authors.},
}
@article {pmid23675944,
year = {2013},
author = {Kuijper, B and Johnstone, RA},
title = {How should parents adjust the size of their young in response to local environmental cues?.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {7},
pages = {1488-1498},
doi = {10.1111/jeb.12156},
pmid = {23675944},
issn = {1420-9101},
mesh = {Adaptation, Psychological ; Animals ; Environment ; Female ; Male ; Models, Biological ; *Models, Theoretical ; Population Dynamics ; Reproduction/*physiology ; },
abstract = {Models of parental investment typically assume that populations are well mixed and homogeneous and have devoted little attention to the impact of spatial variation in the local environment. Here, in a patch-structured model with limited dispersal, we assess to what extent resource-rich and resource-poor mothers should alter the size of their young in response to the local environment in their patch. We show that limited dispersal leads to a correlation between maternal and offspring environments, which favours plastic adjustment of offspring size in response to local survival risk. Strikingly, however, resource-poor mothers are predicted to respond more strongly to local survival risk, whereas resource-rich mothers are predicted to respond less strongly. This lack of sensitivity on the part of resource-rich mothers is favoured because they accrue much of their fitness through dispersing young. By contrast, resource-poor mothers accrue a larger fraction of their fitness through philopatric young and should therefore respond more strongly to local risk. Mothers with more resources gain a larger share of their fitness through dispersing young partly because their fitness in the local patch is constrained by the limited number of local breeding spots. In addition, when resource variation occurs at the patch level, the philopatric offspring of resource-rich mothers face stronger competition from the offspring of other local mothers, who also enjoy abundant resources. The effect of limited local breeding opportunities becomes less pronounced as patch size increases, but the impact of patch-level variation in resources holds up even with many breeders per patch.},
}
@article {pmid23669540,
year = {2013},
author = {Bowers, EK and Sakaluk, SK and Thompson, CF},
title = {Sibling cooperation influences the age of nest leaving in an altricial bird.},
journal = {The American naturalist},
volume = {181},
number = {6},
pages = {775-786},
doi = {10.1086/670244},
pmid = {23669540},
issn = {1537-5323},
mesh = {Age Factors ; Analysis of Variance ; Animals ; *Cooperative Behavior ; Female ; Genetic Fitness ; Male ; Models, Statistical ; *Nesting Behavior ; Proportional Hazards Models ; *Selection, Genetic ; *Siblings ; *Songbirds ; },
abstract = {In altricial birds, siblings raised within a nest usually leave the nest within hours of each other, despite often differing considerably in age. The youngest members of the brood are typically underdeveloped at this time and less likely than their older siblings to survive outside the nest, yet they risk abandonment if they do not fledge with their older siblings. Nest leaving is usually initiated by the older offspring, which may delay this process to provide more time for their younger siblings to mature, increasing the younger siblings' postfledging survival and their own inclusive fitness. We tested this hypothesis in a population of house wrens Troglodytes aedon and found that broods with broad age spans among siblings had longer nestling periods than broods with narrow age spans and that delayed fledging improves the survival and reproductive prospects of younger siblings, although at a potential cost to future siblings. We also manipulated age spans through cross-fostering and found that older foster nestlings postponed fledging when raised with younger broodmates, as predicted if the age of younger nestlings determines the time of fledging. Our results support kin-selection theory and demonstrate that the exact time of fledging is attributable, in part, to sib-sib interactions.},
}
@article {pmid23665207,
year = {2013},
author = {McAvity, DM and Bristow, T and Bunker, E and Dreyer, A},
title = {Perception without self-matching in conditional tag based cooperation.},
journal = {Journal of theoretical biology},
volume = {333},
number = {},
pages = {58-67},
doi = {10.1016/j.jtbi.2013.04.027},
pmid = {23665207},
issn = {1095-8541},
mesh = {*Cooperative Behavior ; Humans ; *Models, Biological ; *Self Concept ; },
abstract = {We consider a model for the evolution of cooperation in a population where individuals may have one of a number of different heritable and distinguishable markers or tags. Individuals interact with each of their neighbors on a square lattice by either cooperating by donating some benefit at a cost to themselves or defecting by doing nothing. The decision to cooperate or defect is contingent on each individual's perception of its interacting partner's tag. Unlike in other tag-based models individuals do not compare their own tag to that of their interaction partner. That is, there is no self-matching. When perception is perfect the cooperation rate is substantially higher than in the usual spatial prisoner's dilemma game when the cost of cooperation is high. The enhancement in cooperation is positively correlated with the number of different tags. The more diverse a population is the more cooperative it becomes. When individuals start with an inability to perceive tags the population evolves to a state where individuals gain at least partial perception. With some reproduction mechanisms perfect perception evolves, but with others the ability to perceive tags is imperfect. We find that perception of tags evolves to lower levels when the cost of cooperation is higher.},
}
@article {pmid23662923,
year = {2013},
author = {Frank, SA},
title = {Natural selection. VII. History and interpretation of kin selection theory.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {6},
pages = {1151-1184},
doi = {10.1111/jeb.12131},
pmid = {23662923},
issn = {1420-9101},
mesh = {*Biological Evolution ; *Selection, Genetic ; },
abstract = {Kin selection theory is a kind of causal analysis. The initial form of kin selection ascribed cause to costs, benefits and genetic relatedness. The theory then slowly developed a deeper and more sophisticated approach to partitioning the causes of social evolution. Controversy followed because causal analysis inevitably attracts opposing views. It is always possible to separate total effects into different component causes. Alternative causal schemes emphasize different aspects of a problem, reflecting the distinct goals, interests and biases of different perspectives. For example, group selection is a particular causal scheme with certain advantages and significant limitations. Ultimately, to use kin selection theory to analyse natural patterns and to understand the history of debates over different approaches, one must follow the underlying history of causal analysis. This article describes the history of kin selection theory, with emphasis on how the causal perspective improved through the study of key patterns of natural history, such as dispersal and sex ratio, and through a unified approach to demographic and social processes. Independent historical developments in the multivariate analysis of quantitative traits merged with the causal analysis of social evolution by kin selection.},
}
@article {pmid23637392,
year = {2013},
author = {Holland, JG and Guidat, FS and Bourke, AF},
title = {Queen control of a key life-history event in a eusocial insect.},
journal = {Biology letters},
volume = {9},
number = {3},
pages = {20130056},
doi = {10.1098/rsbl.2013.0056},
pmid = {23637392},
issn = {1744-957X},
mesh = {Animals ; Bees/growth & development/*physiology ; *Behavior, Animal ; Female ; *Life Cycle Stages ; },
abstract = {In eusocial insects, inclusive fitness theory predicts potential queen-worker conflict over the timing of events in colony life history. Whether queens or workers control the timing of these events is poorly understood. In the bumble-bee Bombus terrestris, queens exhibit a 'switch point' in which they switch from laying diploid eggs yielding females (workers and new queens) to laying haploid eggs yielding males. By rearing foundress queens whose worker offspring were removed as pupae and sexing their eggs using microsatellite genotyping, we found that queens kept in the complete absence of adult workers still exhibit a switch point. Moreover, the timing of their switch points relative to the start of egg-laying did not differ significantly from that of queens allowed to produce normal colonies. The finding that bumble-bee queens can express the switch point in the absence of workers experimentally demonstrates queen control of a key life-history event in eusocial insects. In addition, we found no evidence that workers affect the timing of the switch point either directly or indirectly via providing cues to queens, suggesting that workers do not fully express their interests in queen-worker conflicts over colony life history.},
}
@article {pmid23543424,
year = {2013},
author = {Krupp, DB and Sewall, LA and Lalumière, ML and Sheriff, C and Harris, GT},
title = {Psychopathy, adaptation, and disorder.},
journal = {Frontiers in psychology},
volume = {4},
number = {},
pages = {139},
doi = {10.3389/fpsyg.2013.00139},
pmid = {23543424},
issn = {1664-1078},
abstract = {In a recent study, we found a negative association between psychopathy and violence against genetic relatives. We interpreted this result as a form of nepotism and argued that it failed to support the hypothesis that psychopathy is a mental disorder, suggesting instead that it supports the hypothesis that psychopathy is an evolved life history strategy. This interpretation and subsequent arguments have been challenged in a number of ways. Here, we identify several misunderstandings regarding the harmful dysfunction definition of mental disorder as it applies to psychopathy and regarding the meaning of nepotism. Furthermore, we examine the evidence provided by our critics that psychopathy is associated with other disorders, and we offer a comment on their alternative model of psychopathy. We conclude that there remains little evidence that psychopathy is the product of dysfunctional mechanisms.},
}
@article {pmid23516238,
year = {2013},
author = {Refardt, D and Bergmiller, T and Kümmerli, R},
title = {Altruism can evolve when relatedness is low: evidence from bacteria committing suicide upon phage infection.},
journal = {Proceedings. Biological sciences},
volume = {280},
number = {1759},
pages = {20123035},
doi = {10.1098/rspb.2012.3035},
pmid = {23516238},
issn = {1471-2954},
mesh = {Altruism ; Bacteriophage T4/physiology ; Coliphages/*physiology ; Escherichia coli/genetics/*physiology/*virology ; Flow Cytometry ; Microbial Interactions ; Prophages/*physiology ; Selection, Genetic ; Viral Nonstructural Proteins/metabolism ; },
abstract = {High relatedness among interacting individuals has generally been considered a precondition for the evolution of altruism. However, kin-selection theory also predicts the evolution of altruism when relatedness is low, as long as the cost of the altruistic act is minor compared with its benefit. Here, we demonstrate evidence for a low-cost altruistic act in bacteria. We investigated Escherichia coli responding to the attack of an obligately lytic phage by committing suicide in order to prevent parasite transmission to nearby relatives. We found that bacterial suicide provides large benefits to survivors at marginal costs to committers. The cost of suicide was low, because infected cells are moribund, rapidly dying upon phage infection, such that no more opportunity for reproduction remains. As a consequence of its marginal cost, host suicide was selectively favoured even when relatedness between committers and survivors approached zero. Altogether, our findings demonstrate that low-cost suicide can evolve with ease, represents an effective host-defence strategy, and seems to be widespread among microbes. Moreover, low-cost suicide might also occur in higher organisms as exemplified by infected social insect workers leaving the colony to die in isolation.},
}
@article {pmid23505485,
year = {2013},
author = {Costa-Urrutia, P and Sanvito, S and Victoria-Cota, N and Enríquez-Paredes, L and Gendron, D},
title = {Fine-scale population structure of blue whale wintering aggregations in the Gulf of California.},
journal = {PloS one},
volume = {8},
number = {3},
pages = {e58315},
doi = {10.1371/journal.pone.0058315},
pmid = {23505485},
issn = {1932-6203},
mesh = {*Animal Migration ; Animals ; Balaenoptera/*genetics ; Bayes Theorem ; Bays ; California ; Genetic Variation ; Genetics, Population ; Microsatellite Repeats ; *Seasons ; Spatio-Temporal Analysis ; },
abstract = {Population differentiation in environments without well-defined geographical barriers represents a challenge for wildlife management. Based on a comprehensive database of individual sighting records (1988-2009) of blue whales from the winter/calving Gulf of California, we assessed the fine-scale genetic and spatial structure of the population using individual-based approaches. Skin samples of 187 individuals were analyzed for nine microsatellite loci. A single population with no divergence among years and months and no isolation by distance (Rxy = 0.1-0.001, p>0.05) were found. We ran two bayesian clustering methods using Structure and Geneland softwares in two different ways: 1) a general analysis including all individuals in which a single cluster was identified with both softwares; 2) a specific analysis of females only in which two main clusters (Loreto Bay and northern areas, and San Jose-La Paz Bay area) were revealed by Geneland program. This study provides information indicating that blue whales wintering in the Gulf of California are part of a single population unit and showed a fine-scale structure among females, possibly associated with their high site fidelity, particularly when attending calves. It is likely that the loss of genetic variation is minimized by male mediated gene flow, which may reduce the genetic drift effect. Opportunities for kin selection may also influence calf survival and, in consequence, have a positive impact on population demography in this small and endangered population.},
}
@article {pmid23486437,
year = {2013},
author = {Wu, JJ and He, QQ and Deng, LL and Wang, SC and Mace, R and Ji, T and Tao, Y},
title = {Communal breeding promotes a matrilineal social system where husband and wife live apart.},
journal = {Proceedings. Biological sciences},
volume = {280},
number = {1758},
pages = {20130010},
doi = {10.1098/rspb.2013.0010},
pmid = {23486437},
issn = {1471-2954},
mesh = {Agriculture ; Biological Evolution ; China ; Family Characteristics ; *Family Relations ; Female ; *Genetic Fitness ; Humans ; *Interpersonal Relations ; Male ; Marriage ; Models, Biological ; *Reproduction ; Sibling Relations ; Social Behavior ; },
abstract = {The matrilineal Mosuo of southwest China live in large communal houses where brothers and sisters of three generations live together, and adult males walk to visit their wives only at night; hence males do not reside with their own offspring. This duolocal residence with 'walking' or 'visiting' marriage is described in only a handful of matrilineal peasant societies. Benefits to women of living with matrilineal kin, who cooperate with child-care, are clear. But why any kinship system can evolve where males invest more in their sister's offspring than their own is a puzzle for evolutionary anthropologists. Here, we present a new hypothesis for a matrilineal bias in male investment. We argue that, when household resources are communal, relatedness to the whole household matters more than relatedness to individual offspring. We use an inclusive fitness model to show that the more sisters (and other closely related females) co-reside, the more effort males should spend working on their sister's farm and less on their wife's farm. The model shows that paternity uncertainty may be a cause of lower overall work rates in males, but it is not likely to be the cause of a matrilineal bias. The bias in work effort towards working on their natal farm, and thus the duolocal residence and 'visiting marriage' system, can be understood as maximizing inclusive fitness in circumstances where female kin breed communally.},
}
@article {pmid23471407,
year = {2013},
author = {Hoogland, JL},
title = {Prairie dogs disperse when all close kin have disappeared.},
journal = {Science (New York, N.Y.)},
volume = {339},
number = {6124},
pages = {1205-1207},
doi = {10.1126/science.1231689},
pmid = {23471407},
issn = {1095-9203},
mesh = {*Animal Distribution ; Animals ; *Competitive Behavior ; Female ; Inbreeding ; Male ; *Reproduction ; Sciuridae/anatomy & histology/*physiology ; *Territoriality ; },
abstract = {Because competition decreases inclusive fitness among kin, Hamilton and May predicted that the presence of nearby kin should induce the dispersal of individuals from the natal territory, independent of pressures to avoid inbreeding. Many studies support this landmark prediction, but research over 31 years with prairie dogs reveals the opposite pattern: Young females are 12.5 times more likely to disperse in the absence of mother and siblings for one species, and 5.5 times more likely for another species. Such striking patterns probably occur because cooperation among kin is more important than competition among kin for young prairie dogs. The inability to cooperate with close kin, due to their absence, prompts a search for a new territory where cooperation might be less crucial for survival and reproduction.},
}
@article {pmid23458432,
year = {2013},
author = {Preston, SD},
title = {The origins of altruism in offspring care.},
journal = {Psychological bulletin},
volume = {139},
number = {6},
pages = {1305-1341},
doi = {10.1037/a0031755},
pmid = {23458432},
issn = {1939-1455},
mesh = {*Altruism ; Animals ; Animals, Newborn/psychology ; Behavior, Animal/*physiology ; Caregivers/*psychology ; Decision Making/physiology ; Empathy/physiology ; Family/*psychology ; Haplorhini ; Helping Behavior ; Hominidae ; Humans ; Infant ; Infant, Newborn ; Mothers/psychology ; Motivation/physiology ; Rats ; },
abstract = {The current review aims to unify existing views of altruism through an examination of the biological bases of a fundamental form of giving: altruistic responding. Altruistic responding is most salient during heroic acts of helping but is also observed any time one perceives another's distress or need, which in turn motivates one to help at a current cost to the self. Such aid is simple, observable across species, and rooted in the instincts and circuits that evolved to maximize inclusive fitness through the care of helpless offspring. By design, the system already biases aid to both kin and nonkin under conditions that are largely adaptive. These inherent benefits are also buttressed in primates and humans by known, later-arriving benefits to helping in group-living animals. Evidence for the proposed homology between altruistic responding and offspring retrieval is presented through 10 key shared factors. Conceptually, both require (a) participation by nonmothers, (b) motor competence and expertise, (c) an adaptive opponency between avoidance and approach, and a facilitating role of (d) neonatal vulnerability, (e) salient distress, and (f) rewarding close contact. Physiologically, they also share neurohormonal support from (g) oxytocin, (h) the domain-general mesolimbocortical system, (i) the cingulate cortex, and (j) the orbitofrontal cortex. The framework intermixes ultimate and proximate levels of analysis and unifies existing views by assuming that even complex human behaviors reflect ancient mammalian neural systems that evolved to solve key problems in adaptive ways, with far-reaching consequences for even our most venerated human traits.},
}
@article {pmid23455897,
year = {2013},
author = {Loope, KJ and Seeley, TD and Mattila, HR},
title = {No facultative worker policing in the honey bee (Apis mellifera L.).},
journal = {Die Naturwissenschaften},
volume = {100},
number = {5},
pages = {473-477},
doi = {10.1007/s00114-013-1025-6},
pmid = {23455897},
issn = {1432-1904},
mesh = {Animals ; Bees/*physiology ; Behavior, Animal/*physiology ; Female ; Male ; Sexual Behavior, Animal/physiology ; Social Behavior ; },
abstract = {Kin selection theory predicts that in colonies of social Hymenoptera with multiply mated queens, workers should mutually inhibit ("police") worker reproduction, but that in colonies with singly mated queens, workers should favor rearing workers' sons instead of queens' sons. In line with these predictions, Mattila et al. (Curr Biol 22:2027-2031, 2012) documented increased ovary development among workers in colonies of honey bees with singly mated queens, suggesting that workers can detect and respond adaptively to queen mating frequency and raising the possibility that they facultative police. In a follow-up experiment, we test and reject the hypothesis that workers in single-patriline colonies prefer worker-derived males and are able to reproduce directly; we show that their eggs are policed as strongly as those of workers in colonies with multiply mated queens. Evidently, workers do not respond facultatively to a kin structure that favors relaxed policing and increased direct reproduction. These workers may instead be responding to a poor queen or preparing for possible queen loss.},
}
@article {pmid23451032,
year = {2013},
author = {Kazem, AJ and Widdig, A},
title = {Visual phenotype matching: cues to paternity are present in rhesus macaque faces.},
journal = {PloS one},
volume = {8},
number = {2},
pages = {e55846},
doi = {10.1371/journal.pone.0055846},
pmid = {23451032},
issn = {1932-6203},
support = {8 P40 OD012217-25/OD/NIH HHS/United States ; },
mesh = {Animals ; Cues ; Face/*physiology ; Female ; Humans ; Macaca mulatta ; Male ; *Paternity ; Phenotype ; },
abstract = {The ability to recognize kin and thus behaviourally discriminate between conspecifics based on genetic relatedness is of importance both in acquiring inclusive fitness benefits and to enable optimal inbreeding. In primates, mechanisms allowing recognition of paternal relatives are of particular interest, given that in these mating systems patrilineal information is unlikely to be available via social familiarity. Humans use visual phenotype matching based on facial features to identify their own and other's close relatives, and recent studies suggest similar abilities may be present in other species. However it is unclear to what extent familial resemblances remain detectable against the background levels of relatedness typically found within demes in the wild - a necessary condition if facial cues are to function in kin recognition under natural conditions. Here, we experimentally investigate whether parent-offspring relationships are discernible in rhesus macaque (Macaca mulatta) faces drawn from a large free-ranging population more representative of the latter scenario, and in which genetic relatedness has been well quantified from pedigrees determined via molecular markers. We used the human visual system as a means of integrating multiple types of facial cue simultaneously, and demonstrate that paternal, as well as maternal, resemblance to both sons and daughters can be detected even by human observers. Experts performed better than participants who lacked previous experience working with nonhuman primates. However the finding that even naïve individuals succeeded at the task underlines the strength of the phenotypic cues present in faces.},
}
@article {pmid23436383,
year = {2013},
author = {Scott, NM},
title = {Gesture use by chimpanzees (Pan troglodytes): differences between sexes in inter- and intra-sexual interactions.},
journal = {American journal of primatology},
volume = {75},
number = {6},
pages = {555-567},
doi = {10.1002/ajp.22133},
pmid = {23436383},
issn = {1098-2345},
support = {T32 HD007151/HD/NICHD NIH HHS/United States ; },
mesh = {*Animal Communication ; Animals ; Animals, Zoo ; Female ; *Gestures ; Male ; Pan troglodytes/*psychology ; *Sexual Behavior, Animal ; Video Recording ; },
abstract = {Communication and social relationships are two of the most important aspects of primate life, but few studies have focused on linking these aspects in apes. There are some shared social pressures between the two sexes (e.g., kin selection, alliance formation, and protection against attack), but there are also differences (e.g., mate selection, dispersal, and social ranking systems). The aim of this study was to identify the communication strategies of the sexes with respect to their particular communication partner. I hypothesized the sexes use different strategies in their gestural communication based on their different social pressures. Specifically, males should have more positive intra-sexual relationships than females because of high focus on male-male alliance formation and maintaining high social rank, both of which directly affect their mating opportunities and relationships with all other members of the group. On the other hand, females should have more positive inter-sexual relationships due to the abuse they could receive from insubordination to males and because there is less focus on maintaining multiple, positive relationships with other females. Furthermore, because of differences in social pressures, males should have higher incidence of reassurance in same-sex interactions than females because it should be more important for males to mitigate negative interactions. I analyzed the characteristics of the gesture repertoire and frequency of gesture use for each sex in each of four contexts: (1) aggression, (2) submission, (3) greeting, and (4) reassurance. I looked at intra-sexual and inter-sexual interactions, separately. I found that, indeed, males and females utilize different strategies of gestural communication. I also found that females, but not males, have a distinct gesture strategy for communicating with the opposite sex than for the same sex. This study shows there are distinct strategies utilized by the two sexes and these differences may be explained by their differing social pressures.},
}
@article {pmid23416223,
year = {2013},
author = {Taylor, P},
title = {Inclusive and personal fitness in synergistic evolutionary games on graphs.},
journal = {Journal of theoretical biology},
volume = {325},
number = {},
pages = {76-82},
doi = {10.1016/j.jtbi.2013.02.002},
pmid = {23416223},
issn = {1095-8541},
mesh = {Animals ; *Biological Evolution ; *Game Theory ; Gene Frequency ; Mathematical Concepts ; *Models, Genetic ; Social Behavior ; },
abstract = {I study the evolution of a pair of competing behavioural alleles in a finite graph-structured population when there are non-additive or "synergistic" fitness effects. I begin with the Price equation and extend it to both a personal-fitness and an inclusive-fitness formulation. I thereby obtain an extension of "Hamilton's Rule" to synergistic effects and I calculate and interpret the generalized relatedness coefficients. I present an example of the analysis in a cycle graph with 4 nodes.},
}
@article {pmid23382931,
year = {2013},
author = {Zukewich, J and Kurella, V and Doebeli, M and Hauert, C},
title = {Consolidating birth-death and death-birth processes in structured populations.},
journal = {PloS one},
volume = {8},
number = {1},
pages = {e54639},
doi = {10.1371/journal.pone.0054639},
pmid = {23382931},
issn = {1932-6203},
mesh = {Algorithms ; Biological Evolution ; Computer Simulation ; *Game Theory ; *Models, Biological ; Population Dynamics ; Reproduction ; },
abstract = {Network models extend evolutionary game theory to settings with spatial or social structure and have provided key insights on the mechanisms underlying the evolution of cooperation. However, network models have also proven sensitive to seemingly small details of the model architecture. Here we investigate two popular biologically motivated models of evolution in finite populations: Death-Birth (DB) and Birth-Death (BD) processes. In both cases reproduction is proportional to fitness and death is random; the only difference is the order of the two events at each time step. Although superficially similar, under DB cooperation may be favoured in structured populations, while under BD it never is. This is especially troubling as natural populations do not follow a strict one birth then one death regimen (or vice versa); such constraints are introduced to make models more tractable. Whether structure can promote the evolution of cooperation should not hinge on a simplifying assumption. Here, we propose a mixed rule where in each time step DB is used with probability δ and BD is used with probability 1-δ. We derive the conditions for selection favouring cooperation under the mixed rule for all social dilemmas. We find that the only qualitatively different outcome occurs when using just BD (δ = 0). This case admits a natural interpretation in terms of kin competition counterbalancing the effect of kin selection. Finally we show that, for any mixed BD-DB update and under weak selection, cooperation is never inhibited by population structure for any social dilemma, including the Snowdrift Game.},
}
@article {pmid23372676,
year = {2013},
author = {Pollet, TV and Roberts, SG and Dunbar, RI},
title = {Going that extra mile: individuals travel further to maintain face-to-face contact with highly related kin than with less related kin.},
journal = {PloS one},
volume = {8},
number = {1},
pages = {e53929},
doi = {10.1371/journal.pone.0053929},
pmid = {23372676},
issn = {1932-6203},
mesh = {Adult ; Altruism ; Child ; Emotions ; Family/*psychology ; Female ; Humans ; *Interpersonal Relations ; Likelihood Functions ; Male ; *Object Attachment ; Surveys and Questionnaires ; Travel/*psychology ; },
abstract = {The theory of inclusive fitness has transformed our understanding of cooperation and altruism. However, the proximate psychological underpinnings of altruism are less well understood, and it has been argued that emotional closeness mediates the relationship between genetic relatedness and altruism. In this study, we use a real-life costly behaviour (travel time) to dissociate the effects of genetic relatedness from emotional closeness. Participants travelled further to see more closely related kin, as compared to more distantly related kin. For distantly related kin, the level of emotional closeness mediated this relationship--when emotional closeness was controlled for, there was no effect of genetic relatedness on travel time. However, participants were willing to travel further to visit parents, children and siblings as compared to more distantly related kin, even when emotional closeness was controlled for. This suggests that the mediating effect of emotional closeness on altruism varies with levels of genetic relatedness.},
}
@article {pmid24850977,
year = {2013},
author = {Albers, M and Widdig, A},
title = {The Influence of Kinship on Familiar Natal Migrant Rhesus Macaques (Macaca mulatta).},
journal = {International journal of primatology},
volume = {34},
number = {1},
pages = {99-114},
doi = {10.1007/s10764-012-9651-y},
pmid = {24850977},
issn = {0164-0291},
support = {P40 OD012217/OD/NIH HHS/United States ; },
abstract = {In most primate species, females remain in the natal group with kin while males disperse away from kin around the time of puberty. Philopatric females bias their social behavior toward familiar maternal and paternal kin in several species, but little is known about kin bias in the dispersing sex. Male dispersal is likely to be costly because males encounter an increased risk of predation and death, which might be reduced by dispersing together with kin and/or familiar males (individuals that were born and grew up in same natal group) or into a group containing kin and/or familiar males. Here we studied the influence of kinship on familiar natal migrant rhesus macaques (Macaca mulatta) on Cayo Santiago, Puerto Rico, by combining demographic, behavioral, and genetic data. Our data suggest that kinship influences spatial proximity between recent natal immigrants and males familiar to them. Immigrants were significantly nearer to more closely related familiar males than to more distantly related individuals. Within a familiar subgroup, natal migrants were significantly closer to maternal kin, followed by paternal kin, then non-kin, and finally to males related via both the maternal and paternal line. Spatial proximity between natal immigrants and familiar males did not decrease over time in the new group, suggesting that there is no decline in associations between these individuals within the first months of immigration. Overall, our results might indicate that kinship is important for the dispersing sex, at least during natal dispersal when kin are still available.},
}
@article {pmid23347411,
year = {2013},
author = {Hatchwell, BJ and Sharp, SP and Beckerman, AP and Meade, J},
title = {Ecological and demographic correlates of helping behaviour in a cooperatively breeding bird.},
journal = {The Journal of animal ecology},
volume = {82},
number = {2},
pages = {486-494},
doi = {10.1111/1365-2656.12017},
pmid = {23347411},
issn = {1365-2656},
mesh = {Animals ; *Behavior, Animal ; *Cooperative Behavior ; *Ecosystem ; Models, Biological ; Passeriformes/*physiology ; Population Dynamics ; Reproduction/*physiology ; Time Factors ; },
abstract = {The evolution of cooperation is a persistent problem for evolutionary biologists. In particular, understanding of the factors that promote the expression of helping behaviour in cooperatively breeding species remains weak, presumably because of the diverse nature of ecological and demographic drivers that promote sociality. In this study, we use data from a long-term study of a facultative cooperative breeder, the long-tailed tit Aegithalos caudatus, to investigate the factors influencing annual variation in helping behaviour. Long-tailed tits exhibit redirected helping in which failed breeders may become helpers, usually at a relative's nest; thus, helping is hypothesised to be associated with causes of nest failure and opportunities to renest or help. We tested predictions regarding the relationship between annual measures of cooperative behaviour and four explanatory variables: nest predation rate, length of the breeding season, population-level relatedness and population density. We found that the degree of helping was determined principally by two factors that constrain successful independent reproduction. First, as predicted, cooperative behaviour peaked at intermediate levels of nest predation, when there are both failed breeders (i.e. potential helpers) and active nests (i.e. potential recipients) available. Second, there were more helpers in shorter breeding seasons when opportunities for renesting by failed breeders are more limited. These are novel drivers of helping behaviour in avian cooperative breeding systems, and this study illustrates the difficulty of identifying common ecological or demographic factors underlying the evolution of such systems.},
}
@article {pmid23340259,
year = {2013},
author = {Domondon, AT},
title = {A history of altruism focusing on Darwin, Allee and E.O. Wilson.},
journal = {Endeavour},
volume = {37},
number = {2},
pages = {94-103},
doi = {10.1016/j.endeavour.2012.12.001},
pmid = {23340259},
issn = {1873-1929},
mesh = {*Altruism ; *Biological Evolution ; History, 19th Century ; Humans ; Inheritance Patterns ; Male ; Models, Genetic ; Natural History/*history ; *Selection, Genetic ; Social Adjustment ; },
abstract = {The problem of altruism refers to the apparent difficulty in reconciling the existence of altruists, individuals who reduce their own fitness to increase the fitness of others, with natural selection. A historical and philosophical overview of solutions to this apparent contradiction is presented through a close reading of the key texts of Charles Darwin, Warder C. Allee and Edward O. Wilson. Following an analysis of Darwin's explanation for altruism, I examine the ideas of group selection and kin selection advanced by Allee and Wilson, respectively, Attention is also given to the philosophical implications each associated with their respective solutions.},
}
@article {pmid23339241,
year = {2013},
author = {Boomsma, JJ},
title = {Beyond promiscuity: mate-choice commitments in social breeding.},
journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences},
volume = {368},
number = {1613},
pages = {20120050},
doi = {10.1098/rstb.2012.0050},
pmid = {23339241},
issn = {1471-2970},
mesh = {Adaptation, Biological/*physiology ; Animals ; *Biological Evolution ; Female ; Fertility/physiology ; Genetic Fitness/*genetics ; Insecta/*physiology ; Male ; Mating Preference, Animal/*physiology ; *Models, Biological ; Sexual Behavior, Animal/*physiology ; Species Specificity ; },
abstract = {Obligate eusociality with distinct caste phenotypes has evolved from strictly monogamous sub-social ancestors in ants, some bees, some wasps and some termites. This implies that no lineage reached the most advanced form of social breeding, unless helpers at the nest gained indirect fitness values via siblings that were identical to direct fitness via offspring. The complete lack of re-mating promiscuity equalizes sex-specific variances in reproductive success. Later, evolutionary developments towards multiple queen-mating retained lifetime commitment between sexual partners, but reduced male variance in reproductive success relative to female's, similar to the most advanced vertebrate cooperative breeders. Here, I (i) discuss some of the unique and highly peculiar mating system adaptations of eusocial insects; (ii) address ambiguities that remained after earlier reviews and extend the monogamy logic to the evolution of soldier castes; (iii) evaluate the evidence for indirect fitness benefits driving the dynamics of (in)vertebrate cooperative breeding, while emphasizing the fundamental differences between obligate eusociality and cooperative breeding; (iv) infer that lifetime commitment is a major driver towards higher levels of organization in bodies, colonies and mutualisms. I argue that evolutionary informative definitions of social systems that separate direct and indirect fitness benefits facilitate transparency when testing inclusive fitness theory.},
}
@article {pmid23337317,
year = {2013},
author = {Parvinen, K},
title = {Joint evolution of altruistic cooperation and dispersal in a metapopulation of small local populations.},
journal = {Theoretical population biology},
volume = {85},
number = {},
pages = {12-19},
doi = {10.1016/j.tpb.2013.01.003},
pmid = {23337317},
issn = {1096-0325},
mesh = {*Altruism ; Animal Distribution ; Animals ; *Biological Evolution ; *Cooperative Behavior ; Ecology ; Humans ; },
abstract = {We investigate the joint evolution of public goods cooperation and dispersal in a metapopulation model with small local populations. Altruistic cooperation can evolve due to assortment and kin selection, and dispersal can evolve because of demographic stochasticity, catastrophes and kin selection. Metapopulation structures resulting in assortment have been shown to make selection for cooperation possible. But how does dispersal affect cooperation and vice versa, when both are allowed to evolve as continuous traits? We found four qualitatively different evolutionary outcomes. (1) Monomorphic evolution to full defection with positive dispersal. (2) Monomorphic evolution to an evolutionarily stable state with positive cooperation and dispersal. In this case, parameter changes selecting for increased cooperation typically also select for increased dispersal. (3) Evolutionary branching can result in the evolutionarily stable coexistence of defectors and cooperators. Although defectors could be expected to disperse more than cooperators, here we show that the opposite case is also possible: Defectors tend to disperse less than cooperators when the total amount of cooperation in the dimorphic population is low enough. (4) Selection for too low cooperation can cause the extinction of the evolving population. For moderate catastrophe rates dispersal needs to be initially very frequent for evolutionary suicide to occur. Although selection for less dispersal in principle could prevent such evolutionary suicide, in most cases this rescuing effect is not sufficient, because selection in the cooperation trait is typically much stronger. If the catastrophe rate is large enough, a part of the boundary of viability can be evolutionarily attracting with respect to both strategy components, in which case evolutionary suicide is expected from all initial conditions.},
}
@article {pmid23331930,
year = {2013},
author = {Frank, SA},
title = {Natural selection. VI. Partitioning the information in fitness and characters by path analysis.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {3},
pages = {457-471},
doi = {10.1111/jeb.12066},
pmid = {23331930},
issn = {1420-9101},
mesh = {Alleles ; Animals ; *Evolution, Molecular ; Gene Frequency ; *Genetic Fitness ; Genetics, Population/methods ; Inheritance Patterns ; Models, Genetic ; Phenotype ; Regression Analysis ; *Selection, Genetic ; Social Behavior ; },
abstract = {Three steps aid in the analysis of selection. First, describe phenotypes by their component causes. Components include genes, maternal effects, symbionts and any other predictors of phenotype that are of interest. Second, describe fitness by its component causes, such as an individual's phenotype, its neighbours' phenotypes, resource availability and so on. Third, put the predictors of phenotype and fitness into an exact equation for evolutionary change, providing a complete expression of selection and other evolutionary processes. The complete expression separates the distinct causal roles of the various hypothesized components of phenotypes and fitness. Traditionally, those components are given by the covariance, variance and regression terms of evolutionary models. I show how to interpret those statistical expressions with respect to information theory. The resulting interpretation allows one to read the fundamental equations of selection and evolution as sentences that express how various causes lead to the accumulation of information by selection and the decay of information by other evolutionary processes. The interpretation in terms of information leads to a deeper understanding of selection and heritability, and a clearer sense of how to formulate causal hypotheses about evolutionary process. Kin selection appears as a particular type of causal analysis that partitions social effects into meaningful components.},
}
@article {pmid23303542,
year = {2013},
author = {Bossan, B and Hammerstein, P and Koehncke, A},
title = {We were all young once: an intragenomic perspective on parent-offspring conflict.},
journal = {Proceedings. Biological sciences},
volume = {280},
number = {1754},
pages = {20122637},
doi = {10.1098/rspb.2012.2637},
pmid = {23303542},
issn = {1471-2954},
mesh = {Animals ; *Biological Evolution ; *Conflict (Psychology) ; Female ; *Maternal Behavior ; *Models, Genetic ; Mutation ; Selection, Genetic ; },
abstract = {Parent-offspring conflict (POC) describes the evolutionary conflict between offspring and their parents over parental resource allocation. Offspring are expected to demand more resources than their parents are willing to supply because these offspring are more related to their own than to their siblings' offspring. Kin selection acts to limit these divergent interests. Our model departs from previous models by describing POC as an intragenomic conflict between genes determining life-history traits during infancy or parenthood. We explain why a direct fitness approach that measures the total fitness effect during exactly one generation is required to correctly assess POC in interbrood rivalry. We find that incorrect assumptions in previous models led to an overestimation of the scope of POC. Moreover, we show why the degree of monogamy is more important for POC than previously thought. Overall, we demonstrate that a life-history-centred intragenomic approach is necessary to correctly interpret POCs. We further discuss how our work relates to the current debate about the usefulness of inclusive fitness theory.},
}
@article {pmid23286336,
year = {2013},
author = {Grinsted, L and Bilde, T},
title = {Effects of within-colony competition on body size asymmetries and reproductive skew in a social spider.},
journal = {Journal of evolutionary biology},
volume = {26},
number = {3},
pages = {553-561},
doi = {10.1111/jeb.12072},
pmid = {23286336},
issn = {1420-9101},
mesh = {Adaptation, Physiological ; Animals ; *Body Size ; Competitive Behavior/*physiology ; Feeding Behavior/physiology ; Female ; Linear Models ; Male ; Reproduction ; *Social Behavior ; Species Specificity ; Spiders/*physiology ; Survival Analysis ; Time Factors ; },
abstract = {Reproductive partitioning is a key component of social organization in groups of cooperative organisms. In colonies of permanently social spiders of the genus Stegodyphus less than half of the females reproduce, while all females, including nonreproducers, perform suicidal allo-maternal care. Some theoretical models suggest that reproductive skew is a result of contest competition within colonies, leading to size hierarchies where only the largest females become reproducers. We investigated the effect of competition on within-group body size variation over six months in S. dumicola, by manipulating food level and colony size. We found no evidence that competition leads to increased size asymmetry within colonies, suggesting that contest competition may not be the proximate explanation for reproductive skew. Within-colony body size variation was high already in the juvenile stage, and did not increase over the course of the experiment, suggesting that body size variation is shaped at an early stage. This might facilitate task specialization within colonies and ensure colony-level reproductive output by early allocation of reproductive roles. We suggest that reproductive skew in social spiders may be an adaptation to sociality selected through inclusive fitness benefits of allo-maternal care as well as colony-level benefits maximizing colony survival and production.},
}
@article {pmid23282995,
year = {2013},
author = {Carter, GG and Wilkinson, GS},
title = {Food sharing in vampire bats: reciprocal help predicts donations more than relatedness or harassment.},
journal = {Proceedings. Biological sciences},
volume = {280},
number = {1753},
pages = {20122573},
doi = {10.1098/rspb.2012.2573},
pmid = {23282995},
issn = {1471-2954},
mesh = {*Altruism ; Animals ; Chiroptera/genetics/*physiology ; *Cooperative Behavior ; *Feeding Behavior ; Female ; Genotype ; Male ; Microsatellite Repeats ; *Selection, Genetic ; Videotape Recording ; },
abstract = {Common vampire bats often regurgitate food to roost-mates that fail to feed. The original explanation for this costly helping behaviour invoked both direct and indirect fitness benefits. Several authors have since suggested that food sharing is maintained solely by indirect fitness because non-kin food sharing could have resulted from kin recognition errors, indiscriminate altruism within groups, or harassment. To test these alternatives, we examined predictors of food-sharing decisions under controlled conditions of mixed relatedness and equal familiarity. Over a 2 year period, we individually fasted 20 vampire bats (Desmodus rotundus) and induced food sharing on 48 days. Surprisingly, donors initiated food sharing more often than recipients, which is inconsistent with harassment. Food received was the best predictor of food given across dyads, and 8.5 times more important than relatedness. Sixty-four per cent of sharing dyads were unrelated, approaching the 67 per cent expected if nepotism was absent. Consistent with social bonding, the food-sharing network was consistent and correlated with mutual allogrooming. Together with past work, these findings support the hypothesis that food sharing in vampire bats provides mutual direct fitness benefits, and is not explained solely by kin selection or harassment.},
}
@article {pmid23270702,
year = {2013},
author = {Wakano, JY and Ohtsuki, H and Kobayashi, Y},
title = {A mathematical description of the inclusive fitness theory.},
journal = {Theoretical population biology},
volume = {84},
number = {},
pages = {46-55},
doi = {10.1016/j.tpb.2012.11.007},
pmid = {23270702},
issn = {1096-0325},
mesh = {*Algorithms ; Biological Evolution ; Genetic Fitness/*genetics ; Genetics, Population/statistics & numerical data ; Markov Chains ; *Models, Theoretical ; Plants/genetics ; Selection, Genetic/genetics ; },
abstract = {Recent developments in the inclusive fitness theory have revealed that the direction of evolution can be analytically predicted in a wider class of models than previously thought, such as those models dealing with network structure. This paper aims to provide a mathematical description of the inclusive fitness theory. Specifically, we provide a general framework based on a Markov chain that can implement basic models of inclusive fitness. Our framework is based on the probability distribution of "offspring-to-parent map", from which the key concepts of the theory, such as fitness function, relatedness and inclusive fitness, are derived in a straightforward manner. We prove theorems showing that inclusive fitness always provides a correct prediction on which of two competing genes more frequently appears in the long run in the Markov chain. As an application of the theorems, we prove a general formula of the optimal dispersal rate in the Wright's island model with recurrent mutations. We also show the existence of the critical mutation rate, which does not depend on the number of islands and below which a positive dispersal rate evolves. Our framework can also be applied to lattice or network structured populations.},
}
@article {pmid23251487,
year = {2012},
author = {Loyau, A and Cornuau, JH and Clobert, J and Danchin, E},
title = {Incestuous sisters: mate preference for brothers over unrelated males in Drosophila melanogaster.},
journal = {PloS one},
volume = {7},
number = {12},
pages = {e51293},
doi = {10.1371/journal.pone.0051293},
pmid = {23251487},
issn = {1932-6203},
mesh = {Animals ; Drosophila melanogaster/*physiology ; Female ; Male ; *Sexual Behavior, Animal ; },
abstract = {The literature is full of examples of inbreeding avoidance, while recent mathematical models predict that inbreeding tolerance or even inbreeding preference should be expected under several realistic conditions like e.g. polygyny. We investigated male and female mate preferences with respect to relatedness in the fruit fly D. melanogaster. Experiments offered the choice between a first order relative (full-sibling or parent) and an unrelated individual with the same age and mating history. We found that females significantly preferred mating with their brothers, thus supporting inbreeding preference. Moreover, females did not avoid mating with their fathers, and males did not avoid mating with their sisters, thus supporting inbreeding tolerance. Our experiments therefore add empirical evidence for inbreeding preference, which strengthens the prediction that inbreeding tolerance and preference can evolve under specific circumstances through the positive effects on inclusive fitness.},
}
@article {pmid23251449,
year = {2012},
author = {Hinz, C and Gebhardt, K and Hartmann, AK and Sigman, L and Gerlach, G},
title = {Influence of kinship and MHC class II genotype on visual traits in zebrafish larvae (Danio rerio).},
journal = {PloS one},
volume = {7},
number = {12},
pages = {e51182},
doi = {10.1371/journal.pone.0051182},
pmid = {23251449},
issn = {1932-6203},
mesh = {Animals ; Base Sequence ; DNA Primers ; Eye Color ; *Genotype ; Histocompatibility Antigens Class II/*genetics ; Larva/*physiology ; Skin Pigmentation ; Vision, Ocular/*genetics ; Zebrafish/*genetics/growth & development ; },
abstract = {Kin recognition can drive kin selection and the evolution of social behaviour. In zebrafish (Danio rerio, Hamilton 1822), kin recognition is based on olfactory and visual imprinting processes. If larvae are exposed to visual and chemical cues of kin at day 5 and 6 post fertilization they will recognize kin throughout life, while exposure to non-kin fails to trigger any recognition. Chemical imprinting signals are transcribed by polymorphic genes of the major histocompatibility complex (MHC) code; however, the underlying mechanism for visual imprinting remains unclear. Here we provide evidence for the existence of family-specific differences in morphometry and pigmentation pattern of six day old zebrafish larvae. While rump, tail and body pigmentation were dependent on relatedness, iris pigmentation and morphometry were also influenced by MHC class II genotype. Our study revealed that the MHC not only influences the chemical signature of individuals, but also their visual appearance.},
}
@article {pmid23227237,
year = {2012},
author = {Camperio Ciani, A and Pellizzari, E},
title = {Fecundity of paternal and maternal non-parental female relatives of homosexual and heterosexual men.},
journal = {PloS one},
volume = {7},
number = {12},
pages = {e51088},
doi = {10.1371/journal.pone.0051088},
pmid = {23227237},
issn = {1932-6203},
mesh = {Adult ; Aged ; Aged, 80 and over ; Aging ; *Family ; *Fathers ; Female ; Fertility/*physiology ; *Heterosexuality ; *Homosexuality, Male ; Humans ; Male ; Middle Aged ; *Mothers ; Sample Size ; },
abstract = {A variety of social, developmental, biological and genetic factors influence sexual orientation in males. Thus, several hypotheses have attempted to explain the sustenance of genetic factors that influence male homosexuality, despite decreased fecundity within the homosexuals. Kin selection, the existence of maternal effects and two forms of balancing selection, sexually antagonistic selection and overdominance, have been proposed as compensatory mechanisms for reduced homosexual fecundity. Here, we suggest that the empirical support for kin selection and maternal effects cannot account for the low universal frequency and stability of the distribution of homosexuals. To identify the responsible compensatory mechanism, we analyzed fecundity in 2,100 European female relatives, i.e., aunts and grandmothers, of either homosexual or heterosexual probands who were matched in terms of age, culture and sampling strategy. Female relatives were chosen to avoid the sampling bias of the fraternal birth order effect, which occurs when indirectly sampling mothers though their homosexual sons. We observed that the maternal aunts and grandmothers of homosexual probands were significantly more fecund compared with the maternal aunts and maternal grandmothers of the heterosexual probands. No difference in fecundity was observed in the paternal female lines (grandmothers or aunts) from either of the two proband groups. Moreover, due to the selective increase in maternal female fecundity, the total female fecundity was significantly higher in homosexual than heterosexual probands, thus compensating for the reduced fecundity of homosexuals. Altogether, these data support an X-linked multi-locus sexually antagonistic hypothesis rather than an autosomal multi-locus overdominance hypothesis.},
}
@article {pmid23212709,
year = {2013},
author = {Gibson, AH},
title = {Edward o. Wilson and the organicist tradition.},
journal = {Journal of the history of biology},
volume = {46},
number = {4},
pages = {599-630},
doi = {10.1007/s10739-012-9347-3},
pmid = {23212709},
issn = {0022-5010},
abstract = {Edward O. Wilson's recent decision to abandon kin selection theory has sent shockwaves throughout the biological sciences. Over the past two years, more than a hundred biologists have signed letters protesting his reversal. Making sense of Wilson's decision and the controversy it has spawned requires familiarity with the historical record. This entails not only examining the conditions under which kin selection theory first emerged, but also the organicist tradition against which it rebelled. In similar fashion, one must not only examine Wilson's long career, but also those thinkers who influenced him most, especially his intellectual grandfather, William Morton Wheeler (1865-1937). Wilson belongs to a long line of organicists, biologists whose research highlighted integration and coordination, many of whom struggled over the exact same biological riddles that have long defined Wilson's career. Drawing inspiration (and sometimes ideas) from these intellectual forebears, Wilson is confident that he has finally identified the origin of the social impulse.},
}
@article {pmid23209792,
year = {2012},
author = {Antfolk, J and Lieberman, D and Santtila, P},
title = {Fitness costs predict inbreeding aversion irrespective of self-involvement: support for hypotheses derived from evolutionary theory.},
journal = {PloS one},
volume = {7},
number = {11},
pages = {e50613},
doi = {10.1371/journal.pone.0050613},
pmid = {23209792},
issn = {1932-6203},
mesh = {Adult ; Biological Evolution ; *Consanguinity ; Female ; Humans ; Male ; Sexual Behavior/*physiology ; Young Adult ; },
abstract = {It is expected that in humans, the lowered fitness of inbred offspring has produced a sexual aversion between close relatives. Generally, the strength of this aversion depends on the degree of relatedness between two individuals, with closer relatives inciting greater aversion than more distant relatives. Individuals are also expected to oppose acts of inbreeding that do not include the self, as inbreeding between two individuals posits fitness costs not only to the individuals involved in the sexual act, but also to their biological relatives. Thus, the strength of inbreeding aversion should be predicted by the fitness costs an inbred child posits to a given individual, irrespective of this individual's actual involvement in the sexual act. To test this prediction, we obtained information about the family structures of 663 participants, who reported the number of same-sex siblings, opposite-sex siblings, opposite-sex half siblings and opposite-sex cousins. Each participant was presented with three different types of inbreeding scenarios: 1) Participant descriptions, in which participants themselves were described as having sex with an actual opposite-sex relative (sibling, half sibling, or cousin); 2) Related third-party descriptions, in which participants' actual same-sex siblings were described as having sex with their actual opposite-sex relatives; 3) Unrelated third-party descriptions, in which individuals of the same sex as the participants but unrelated to them were described as having sex with opposite-sex relatives. Participants rated each description on the strength of sexual aversion (i.e., disgust-reaction). We found that unrelated third-party descriptions elicited less disgust than related third-party and participant descriptions. Related third-party and participant descriptions elicited similar levels of disgust suggesting that the strength of inbreeding aversion is predicted by inclusive fitness costs. Further, in the related and unrelated conditions alike, the strength of inbreeding aversion was positively associated with the degree of relatedness between those described in the descriptions.},
}
@article {pmid23206136,
year = {2012},
author = {Jaffé, R and Garcia-Gonzalez, F and den Boer, SP and Simmons, LW and Baer, B},
title = {Patterns of paternity skew among polyandrous social insects: what can they tell us about the potential for sexual selection?.},
journal = {Evolution; international journal of organic evolution},
volume = {66},
number = {12},
pages = {3778-3788},
doi = {10.1111/j.1558-5646.2012.01721.x},
pmid = {23206136},
issn = {1558-5646},
mesh = {Animals ; Female ; *Hymenoptera ; Male ; Phylogeny ; Regression Analysis ; Selection, Genetic ; *Sexual Behavior, Animal ; },
abstract = {Monogamy results in high genetic relatedness among offspring and thus it is generally assumed to be favored by kin selection. Female multiple mating (polyandry) has nevertheless evolved several times in the social Hymenoptera (ants, bees, and wasps), and a substantial amount of work has been conducted to understand its costs and benefits. Relatedness and inclusive fitness benefits are, however, not only influenced by queen mating frequency but also by paternity skew, which is a quantitative measure of paternity biases among the offspring of polyandrous females. We performed a large-scale phylogenetic analysis of paternity skew across polyandrous social Hymenoptera. We found a general and significant negative association between paternity frequency and paternity skew. High paternity skew, which increases relatedness among colony members and thus maximizes inclusive fitness gains, characterized species with low paternity frequency. However, species with highly polyandrous queens had low paternity skew, with paternity equalized among potential sires. Equal paternity shares among fathers are expected to maximize fitness benefits derived from genetic diversity among offspring. We discuss the potential for postcopulatory sexual selection to influence patterns of paternity in social insects, and suggest that sexual selection may have played a key, yet overlooked role in social evolution.},
}
@article {pmid23198727,
year = {2012},
author = {Kessler, SE and Scheumann, M and Nash, LT and Zimmermann, E},
title = {Paternal kin recognition in the high frequency / ultrasonic range in a solitary foraging mammal.},
journal = {BMC ecology},
volume = {12},
number = {},
pages = {26},
doi = {10.1186/1472-6785-12-26},
pmid = {23198727},
issn = {1472-6785},
mesh = {Animals ; Cheirogaleidae/*physiology ; Female ; Male ; Recognition (Psychology) ; Social Behavior ; Ultrasonics ; *Vocalization, Animal ; },
abstract = {BACKGROUND: Kin selection is a driving force in the evolution of mammalian social complexity. Recognition of paternal kin using vocalizations occurs in taxa with cohesive, complex social groups. This is the first investigation of paternal kin recognition via vocalizations in a small-brained, solitary foraging mammal, the grey mouse lemur (Microcebus murinus), a frequent model for ancestral primates. We analyzed the high frequency/ultrasonic male advertisement (courtship) call and alarm call.

RESULTS: Multi-parametric analyses of the calls' acoustic parameters and discriminant function analyses showed that advertisement calls, but not alarm calls, contain patrilineal signatures. Playback experiments controlling for familiarity showed that females paid more attention to advertisement calls from unrelated males than from their fathers. Reactions to alarm calls from unrelated males and fathers did not differ.

CONCLUSIONS: 1) Findings provide the first evidence of paternal kin recognition via vocalizations in a small-brained, solitarily foraging mammal. 2) High predation, small body size, and dispersed social systems may select for acoustic paternal kin recognition in the high frequency/ultrasonic ranges, thus limiting risks of inbreeding and eavesdropping by predators or conspecific competitors. 3) Paternal kin recognition via vocalizations in mammals is not dependent upon a large brain and high social complexity, but may already have been an integral part of the dispersed social networks from which more complex, kin-based sociality emerged.},
}
@article {pmid23195920,
year = {2013},
author = {Archetti, M},
title = {Evolution of polygamous marriage by maximization of inclusive fitness.},
journal = {Journal of theoretical biology},
volume = {319},
number = {},
pages = {134-143},
doi = {10.1016/j.jtbi.2012.11.017},
pmid = {23195920},
issn = {1095-8541},
mesh = {Female ; Humans ; Male ; *Marriage ; *Models, Theoretical ; },
abstract = {The majority of human societies practice polygynous marriage, in line with the typical mating pattern found in mammals. Polygyny in humans is often associated with the transfer of wealth to a male's sister's offspring, and it has been suggested that this "mother's brother phenomenon" is adaptive when paternity confidence is low. Polyandry, on the other hand, while virtually unknown in mammals, is practiced by a few human societies, and it has been suggested that this is adaptive if the co-husbands are genetically related. The evolution of human marriage strategies, therefore, can be studied in the framework of kin selection and game theory, as strategic transmission of wealth by males and strategic paternity allocation by females can evolve to maximize inclusive fitness. Here I analyse the stability of polygynous and polyandrous marriage using a game theoretical model previously developed to study monogamy. I show that the "mother's brother phenomenon" depends on the degree of resource depletion through division, whereas the paternity threshold commonly discussed in the anthropological literature is largely irrelevant. Resource depletion through division is also the major determinant of the stability of polyandry, whereas relatedness between co-husbands is not essential. Finally, I show that when females control the transfer of their own resources, monogamy is stable under more general conditions than previously believed.},
}
@article {pmid23182969,
year = {2012},
author = {Gesselman, AN and Webster, GD},
title = {Inclusive fitness affects both prosocial and antisocial behavior: target gender and insult domain moderate the link between genetic relatedness and aggression.},
journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior},
volume = {10},
number = {4},
pages = {750-761},
pmid = {23182969},
issn = {1474-7049},
mesh = {Adolescent ; Adult ; Aggression/*psychology ; *Family Relations ; Female ; Humans ; *Interpersonal Relations ; Male ; Middle Aged ; Young Adult ; },
abstract = {Although prior research has examined the relationship between genetic relatedness and helping behavior (Burnstein, Crandall, and Kitayama, 1994), less is known about its role in aggressive responses to insults (Fitzgerald and Ketterer, 2011). Drawing on inclusive fitness theory (Hamilton, 1964) and the Kinship, Acceptance, and Rejection Model of Altruism and Aggression (KARMAA; Webster, 2008; Webster et al., 2012), we designed a 2 (participant gender) × 2 (target gender) × 2 (insult: status vs. reproductive) × 3 (relatedness: stranger vs. cousin vs. sibling) between-person experiment in which 489 participants (a) read vignettes in which a stranger, cousin, or sibling was insulted and (b) reported their emotional reaction and retaliation likelihood (six-item α = .91) in response to the insult. Consistent with theory and prior research, men were significantly more aggressive than women, and people were significantly more aggressive responding to insults against kin than non-kin. These findings support theoretically-derived, dynamic, and domain-specific links among insults, gender, relatedness, and aggression.},
}
@article {pmid23179098,
year = {2012},
author = {Chernenko, A and Holman, L and Helanterä, H and Sundström, L},
title = {Cuticular chemistry of males and females in the ant Formica fusca.},
journal = {Journal of chemical ecology},
volume = {38},
number = {12},
pages = {1474-1482},
doi = {10.1007/s10886-012-0217-4},
pmid = {23179098},
issn = {1573-1561},
mesh = {Animals ; Ants/*chemistry ; Chromatography, Gas ; Discriminant Analysis ; Female ; Hydrocarbons/*analysis ; Male ; Principal Component Analysis ; },
abstract = {Communication between organisms involves visual, auditory, and olfactory pathways. In solitary insects, chemical recognition cues are influenced mainly by selection regimes related to species recognition and sexual selection. In social insects, chemical recognition cues have an additional role in mediating recognition of society members and, thereby, allowing kin selection to operate. Here, we examined whether cuticular hydrocarbon profiles are sex-specific and whether males and young queens of the ant Formica fusca have colony-specific profiles. We also investigated whether there is a relationship between genetic relatedness and chemical diversity within colonies. We demonstrated that female and male sexuals do not have unique sex-specific compounds, but that there are quantitative chemical differences between the sexes. Out of the 51 cuticular hydrocarbon compounds identified, 10 showed a significant quantitative difference between males and females. We also showed that both males and females have a significant colony-specific component in their profiles. Finally, we found a negative correlation between within-colony relatedness and within-colony chemical diversity of branched, but not linear compounds. This suggests that colonies with multiple matri- or patrilines also have a significantly greater chemical diversity.},
}
@article {pmid23094799,
year = {2012},
author = {Seppä, P and Johansson, H and Gyllenstrand, N and Pálsson, S and Pamilo, P},
title = {Mosaic structure of native ant supercolonies.},
journal = {Molecular ecology},
volume = {21},
number = {23},
pages = {5880-5891},
doi = {10.1111/mec.12070},
pmid = {23094799},
issn = {1365-294X},
mesh = {Animals ; Ants/*genetics ; Bayes Theorem ; DNA, Mitochondrial ; Finland ; *Genetic Variation ; *Genetics, Population ; Haplotypes ; Models, Genetic ; Sweden ; },
abstract = {According to the inclusive fitness theory, some degree of positive relatedness is required for the evolution and maintenance of altruism. However, ant colonies are sometimes large interconnected networks of nests, which are genetically homogenous entities, causing a putative problem for the theory. We studied spatial structure and genetic relatedness in two supercolonies of the ant Formica exsecta, using nuclear and mitochondrial markers. We show that there may be multiple pathways to supercolonial social organization leading to different spatial genetic structures. One supercolony formed a genetically homogenous population dominated by a single mtDNA haplotype, as expected if founded by a small number of colonizers, followed by nest propagation by budding and domination of the habitat patch. The other supercolony had several haplotypes, and the spatial genetic structure was a mosaic of nuclear and mitochondrial clusters. Genetic diversity probably originated from long-range dispersal, and the mosaic population structure is likely a result of stochastic short-range dispersal of individuals. Such a mosaic spatial structure is apparently discordant with the current knowledge about the integrity of ant colonies. Relatedness was low in both populations when estimated among nestmates, but increased significantly when estimated among individuals sharing the same genetic cluster or haplogroup. The latter association indicates the important historical role of queen dispersal in the determination of the spatial genetic structure.},
}
@article {pmid23093096,
year = {2012},
author = {Grinsted, L and Agnarsson, I and Bilde, T},
title = {Subsocial behaviour and brood adoption in mixed-species colonies of two theridiid spiders.},
journal = {Die Naturwissenschaften},
volume = {99},
number = {12},
pages = {1021-1030},
doi = {10.1007/s00114-012-0983-4},
pmid = {23093096},
issn = {1432-1904},
mesh = {Aggression ; Animals ; Behavior, Animal/*physiology ; DNA Barcoding, Taxonomic ; Electron Transport Complex IV/genetics ; Female ; Indonesia ; Male ; Phylogeny ; RNA, Ribosomal, 28S/genetics ; Sex Ratio ; *Social Behavior ; Species Specificity ; Spiders/genetics/*physiology ; },
abstract = {Cooperation and group living often evolves through kin selection. However, associations between unrelated organisms, such as different species, can evolve if both parties benefit from the interaction. Group living is rare in spiders, but occurs in cooperative, permanently social spiders, as well as in territorial, colonial spiders. Mixed species spider colonies, involving closely related species, have rarely been documented. We examined social interactions in newly discovered mixed-species colonies of theridiid spiders on Bali, Indonesia. Our aim was to test the degree of intra- and interspecific tolerance, aggression and cooperation through behavioural experiments and examine the potential for adoption of foreign brood. Morphological and genetic analyses confirmed that colonies consisted of two related species Chikunia nigra (O.P. Cambridge, 1880) new combination (previously Chrysso nigra) and a yet undescribed Chikunia sp. Females defended territories and did not engage in cooperative prey capture, but interestingly, both species seemed to provide extended maternal care of young and indiscriminate care for foreign brood. Future studies may reveal whether these species adopt only intra-specific young, or also inter-specifically. We classify both Chikunia species subsocial and intra- and interspecifically colonial, and discuss the evolutionary significance of a system where one or both species may potentially benefit from mutual tolerance and brood adoption.},
}
@article {pmid23075837,
year = {2012},
author = {Fortunato, L},
title = {The evolution of matrilineal kinship organization.},
journal = {Proceedings. Biological sciences},
volume = {279},
number = {1749},
pages = {4939-4945},
doi = {10.1098/rspb.2012.1926},
pmid = {23075837},
issn = {1471-2954},
mesh = {*Biological Evolution ; *Family Characteristics ; Female ; Game Theory ; Humans ; Male ; *Marriage ; Models, Biological ; Models, Theoretical ; *Sexual Behavior ; Socioeconomic Factors ; },
abstract = {Matrilineal kinship organization is a human social system that emphasizes interactions between matrilineal kin, i.e. individuals related only through females. The 'matrilineal puzzle' refers to the potential for tension characteristic of this social system, owing to the conflict between the interests and responsibilities of men in their roles as brother/uncle versus husband/father. From an evolutionary perspective, matrilineal kinship organization is puzzling when it diverts investment of resources from the individuals who provide the potentially highest reproductive returns. I use a game-theoretic framework to investigate a particular form of matrilineal inheritance--the transfer of property from a maternal uncle to a sororal nephew. The analysis reveals two mechanisms that may make this strategy a stable evolutionary outcome. First, a polygynous male has multiple wives, and hence multiple brothers-in-law; with matrilineal inheritance, each additional brother-in-law may transfer resources to the male's wife's offspring, thus potentially contributing to the male's inclusive fitness. Second, the husband of a polyandrous female is effectively 'sharing' paternity with other men; depending on the number of husbands, he may be better off investing in his sister's offspring. I conclude by discussing how these results address the challenges posed by the occurrence of matrilineal kinship organization.},
}
@article {pmid23049791,
year = {2012},
author = {Seppä, P and Queller, DC and Strassmann, JE},
title = {Why wasp foundresses change nests: relatedness, dominance, and nest quality.},
journal = {PloS one},
volume = {7},
number = {9},
pages = {e45386},
doi = {10.1371/journal.pone.0045386},
pmid = {23049791},
issn = {1932-6203},
mesh = {Animal Communication ; Animals ; *Choice Behavior ; Competitive Behavior/*physiology ; Cooperative Behavior ; Female ; Genetic Fitness/*physiology ; Homing Behavior ; Microsatellite Repeats ; Nesting Behavior/*physiology ; Reproduction/*physiology ; Seasons ; Sexual Behavior, Animal ; Social Behavior ; Wasps/*physiology ; },
abstract = {The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests. Females can become helpers or egglayers, effectively workers or queens. What they actually do can be predicted by a combination of ecological and relatedness factors. Advantages through increased lifetime success of individuals and nests drives foundresses of the social wasp Polistes from solitary to social nest founding. We studied reproductive options of spring foundresses of P. carolina by monitoring individually-marked wasps and assessing reproductive success of each foundress by using DNA microsatellites. We examined what behavioral decisions foundresses make after relaxing a strong ecological constraint, shortage of nesting sites. We also look at the reproductive consequences of different behaviors. As in other Polistes, the most successful strategy for a foundress was to initiate a nest as early as possible and then accept others as subordinates. A common feature for many P. carolina foundresses was, however, that they reassessed their reproductive options by actively monitoring other nests at the field site and sometimes moving permanently to new nests should that offer better (inclusive) fitness prospects compared to their original nests. A clear motivation for moving to new nests was high genetic relatedness; by the end of the foundress period all females were on nests with full sisters.},
}
@article {pmid23029158,
year = {2012},
author = {File, AL and Klironomos, J and Maherali, H and Dudley, SA},
title = {Plant kin recognition enhances abundance of symbiotic microbial partner.},
journal = {PloS one},
volume = {7},
number = {9},
pages = {e45648},
doi = {10.1371/journal.pone.0045648},
pmid = {23029158},
issn = {1932-6203},
mesh = {Mycorrhizae/*physiology ; *Plant Physiological Phenomena ; Plant Roots/microbiology ; Plants/*microbiology ; *Symbiosis ; },
abstract = {BACKGROUND: The stability of cooperative interactions among different species can be compromised by cheating. In the plant-mycorrhizal fungi symbiosis, a single mycorrhizal network may interact with many plants, providing the opportunity for individual plants to cheat by obtaining nutrients from the fungi without donating carbon. Here we determine whether kin selection may favour plant investment in the mycorrhizal network, reducing the incentive to cheat when relatives interact with a single network.

We show that mycorrhizal network size and root colonization were greater when Ambrosia artemisiifolia L. was grown with siblings compared to strangers. Soil fungal abundance was positively correlated with group leaf nitrogen, and increased root colonization was associated with a reduced number of pathogen-induced root lesions, indicating greater benefit to plants grown with siblings.

CONCLUSIONS/SIGNIFICANCE: Plants can benefit their relatives through investment in mycorrhizal fungi, and kin selection in plants could promote the persistence of the mycorrhizal symbiosis.},
}
@article {pmid22984064,
year = {2012},
author = {Foster, EA and Franks, DW and Mazzi, S and Darden, SK and Balcomb, KC and Ford, JK and Croft, DP},
title = {Adaptive prolonged postreproductive life span in killer whales.},
journal = {Science (New York, N.Y.)},
volume = {337},
number = {6100},
pages = {1313},
doi = {10.1126/science.1224198},
pmid = {22984064},
issn = {1095-9203},
support = {//Biotechnology and Biological Sciences Research Council/United Kingdom ; },
mesh = {Animals ; Female ; *Longevity ; Male ; Proportional Hazards Models ; *Reproduction ; Whale, Killer/*physiology ; },
abstract = {Prolonged life after reproduction is difficult to explain evolutionarily unless it arises as a physiological side effect of increased longevity or it benefits related individuals (i.e., increases inclusive fitness). There is little evidence that postreproductive life spans are adaptive in nonhuman animals. By using multigenerational records for two killer whale (Orcinus orca) populations in which females can live for decades after their final parturition, we show that postreproductive mothers increase the survival of offspring, particularly their older male offspring. This finding may explain why female killer whales have evolved the longest postreproductive life span of all nonhuman animals.},
}
@article {pmid22977147,
year = {2012},
author = {Taylor, P and Maciejewski, W},
title = {An inclusive fitness analysis of synergistic interactions in structured populations.},
journal = {Proceedings. Biological sciences},
volume = {279},
number = {1747},
pages = {4596-4603},
doi = {10.1098/rspb.2012.1408},
pmid = {22977147},
issn = {1471-2954},
mesh = {Animals ; *Behavior, Animal ; Columbidae/physiology ; Game Theory ; Gene Frequency ; Hawks/physiology ; *Models, Theoretical ; *Social Behavior ; },
abstract = {We study the evolution of a pair of competing behavioural alleles in a structured population when there are non-additive or 'synergistic' fitness effects. Under a form of weak selection and with a simple symmetry condition between a pair of competing alleles, Tarnita et al. provide a surprisingly simple condition for one allele to dominate the other. Their condition can be obtained from an analysis of a corresponding simpler model in which fitness effects are additive. Their result uses an average measure of selective advantage where the average is taken over the long-term--that is, over all possible allele frequencies--and this precludes consideration of any frequency dependence the allelic fitness might exhibit. However, in a considerable body of work with non-additive fitness effects--for example, hawk-dove and prisoner's dilemma games--frequency dependence plays an essential role in the establishment of conditions for a stable allele-frequency equilibrium. Here, we present a frequency-dependent generalization of their result that provides an expression for allelic fitness at any given allele frequency p. We use an inclusive fitness approach and provide two examples for an infinite structured population. We illustrate our results with an analysis of the hawk-dove game.},
}
@article {pmid22973244,
year = {2012},
author = {Krupp, DB and Sewall, LA and Lalumière, ML and Sheriff, C and Harris, GT},
title = {Nepotistic patterns of violent psychopathy: evidence for adaptation?.},
journal = {Frontiers in psychology},
volume = {3},
number = {},
pages = {305},
doi = {10.3389/fpsyg.2012.00305},
pmid = {22973244},
issn = {1664-1078},
abstract = {Psychopaths routinely disregard social norms by engaging in selfish, antisocial, often violent behavior. Commonly characterized as mentally disordered, recent evidence suggests that psychopaths are executing a well-functioning, if unscrupulous strategy that historically increased reproductive success at the expense of others. Natural selection ought to have favored strategies that spared close kin from harm, however, because actions affecting the fitness of genetic relatives contribute to an individual's inclusive fitness. Conversely, there is evidence that mental disorders can disrupt psychological mechanisms designed to protect relatives. Thus, mental disorder and adaptation accounts of psychopathy generate opposing hypotheses: psychopathy should be associated with an increase in the victimization of kin in the former account but not in the latter. Contrary to the mental disorder hypothesis, we show here in a sample of 289 violent offenders that variation in psychopathy predicts a decrease in the genetic relatedness of victims to offenders; that is, psychopathy predicts an increased likelihood of harming non-relatives. Because nepotistic inhibition in violence may be caused by dispersal or kin discrimination, we examined the effects of psychopathy on (1) the dispersal of offenders and their kin and (2) sexual assault frequency (as a window on kin discrimination). Although psychopathy was negatively associated with coresidence with kin and positively associated with the commission of sexual assault, it remained negatively associated with the genetic relatedness of victims to offenders after removing cases of offenders who had coresided with kin and cases of sexual assault from the analyses. These results stand in contrast to models positing psychopathy as a pathology, and provide support for the hypothesis that psychopathy reflects an evolutionary strategy largely favoring the exploitation of non-relatives.},
}
@article {pmid22913671,
year = {2012},
author = {Lahdenperä, M and Gillespie, DOS and Lummaa, V and Russell, AF},
title = {Severe intergenerational reproductive conflict and the evolution of menopause.},
journal = {Ecology letters},
volume = {15},
number = {11},
pages = {1283-1290},
doi = {10.1111/j.1461-0248.2012.01851.x},
pmid = {22913671},
issn = {1461-0248},
mesh = {Adolescent ; Adult ; *Biological Evolution ; Death ; Female ; Finland ; Genetic Fitness ; Humans ; *Intergenerational Relations ; Menopause/*physiology ; Middle Aged ; Models, Theoretical ; Parturition ; *Reproduction ; Risk ; Selection, Genetic ; Survival ; Young Adult ; },
abstract = {Human menopause is ubiquitous among women and is uninfluenced by modernity. In addition, it remains an evolutionary puzzle: studies have largely failed to account for diminishing selection on reproduction beyond 50 years. Using a 200-year dataset on pre-industrial Finns, we show that an important component is between-generation reproductive conflict among unrelated women. Simultaneous reproduction by successive generations of in-laws was associated with declines in offspring survivorship of up to 66%. An inclusive fitness model revealed that incorporation of the fitness consequences of simultaneous intergenerational reproduction between in-laws, with those of grandmothering and risks of dying in childbirth, were sufficient to generate selection against continued reproduction beyond 51 years. Decomposition of model estimates suggested that the former two were most influential in generating selection against continued reproduction. We propose that menopause evolved, in part, because of age-specific increases in opportunities for intergenerational cooperation and reproductive competition under ecological scarcity.},
}
@article {pmid22911845,
year = {2012},
author = {Goropashnaya, AV and Fedorov, VB and Seifert, B and Pamilo, P},
title = {Phylogenetic relationships of Palaearctic Formica species (Hymenoptera, Formicidae) based on mitochondrial cytochrome B sequences.},
journal = {PloS one},
volume = {7},
number = {7},
pages = {e41697},
doi = {10.1371/journal.pone.0041697},
pmid = {22911845},
issn = {1932-6203},
mesh = {Animals ; Ants/*genetics ; Base Sequence ; Cytochromes b/*genetics ; DNA, Mitochondrial/*genetics ; Evolution, Molecular ; Genetic Variation ; Haplotypes/genetics ; Likelihood Functions ; Molecular Sequence Data ; *Paleontology ; *Phylogeny ; Species Specificity ; },
abstract = {Ants of genus Formica demonstrate variation in social organization and represent model species for ecological, behavioral, evolutionary studies and testing theoretical implications of the kin selection theory. Subgeneric division of the Formica ants based on morphology has been questioned and remained unclear after an allozyme study on genetic differentiation between 13 species representing all subgenera was conducted. In the present study, the phylogenetic relationships within the genus were examined using mitochondrial DNA sequences of the cytochrome b and a part of the NADH dehydrogenase subunit 6. All 23 Formica species sampled in the Palaearctic clustered according to the subgeneric affiliation except F. uralensis that formed a separate phylogenetic group. Unlike Coptoformica and Formica s. str., the subgenus Serviformica did not form a tight cluster but more likely consisted of a few small clades. The genetic distances between the subgenera were around 10%, implying approximate divergence time of 5 Myr if we used the conventional insect divergence rate of 2% per Myr. Within-subgenus divergence estimates were 6.69% in Serviformica, 3.61% in Coptoformica, 1.18% in Formica s. str., which supported our previous results on relatively rapid speciation in the latter subgenus. The phylogeny inferred from DNA sequences provides a necessary framework against which the evolution of social traits can be compared. We discuss implications of inferred phylogeny for the evolution of social traits.},
}
@article {pmid22860635,
year = {2013},
author = {Abild, ML and VanderLaan, DP and Vasey, PL},
title = {No evidence for treating friends' children like kin in Canadian androphilic men.},
journal = {Journal of sex research},
volume = {50},
number = {7},
pages = {697-703},
doi = {10.1080/00224499.2012.681404},
pmid = {22860635},
issn = {1559-8519},
mesh = {Adult ; Canada ; Child ; Child Rearing/psychology ; Cross-Cultural Comparison ; Family/*psychology ; Female ; Friends/*psychology ; Homosexuality, Male/*psychology ; Humans ; Male ; Sexuality/*psychology ; },
abstract = {Given that same-sex sexual orientation is associated with lower reproductive success, how have genes associated with male androphilia (i.e., male sexual attraction/arousal to adult men) persisted over evolutionary time? The Kin Selection Hypothesis proposes that by directing valuable resources toward kin, androphilic men may enhance their indirect fitness and thereby offset the fitness costs of not reproducing directly. Support for this hypothesis has been garnered from studies conducted in Samoa, but not from studies of "gay" men in industrialized cultures (i.e., Canada, Japan, United Kingdom, and the United States). This cross-cultural difference may be due to relatively greater geographic and familial disconnect experienced by androphilic "gay" men in industrialized cultures. This article reasons that in more industrialized settings, friends' children may serve as non-adaptive proxies for nieces and nephews. Hence, it was predicted that Canadian androphilic men would exhibit elevated altruistic tendencies toward their friends' children compared with gynephilic men and androphilic women. This prediction was not supported. However, in line with previous research, the results indicated that androphilic women are more likely to behave altruistically toward friends' children compared to gynephilic men. Other possible explanations for the existing cross-cultural discrepancy in altruistic tendencies toward nieces and nephews are discussed.},
}
@article {pmid22837829,
year = {2012},
author = {Asaduzzaman, SM and Wild, G},
title = {The evolution of dispersal conditioned on migration status.},
journal = {Ecology and evolution},
volume = {2},
number = {4},
pages = {822-843},
doi = {10.1002/ece3.99},
pmid = {22837829},
issn = {2045-7758},
abstract = {We consider a model for the evolution of dispersal of offspring. Dispersal is treated as a parental trait that is expressed conditional upon a parent's own "migration status," that is, whether a parent, itself, is native or nonnative to the area in which it breeds. We compare the evolution of this kind of conditional dispersal to the evolution of unconditional dispersal, in order to determine the extent to which the former changes predictions about population-wide levels of dispersal. We use numerical simulations of an inclusive-fitness model, and individual-based simulations to predict population-average dispersal rates for the case in which dispersal based on migration status occurs. When our model predictions are compared to predictions that neglect conditional dispersal, observed differences between rates are only slight, and never exceed 0.06. While the effect of dispersal conditioned upon migration status could be detected in a carefully designed experiment, we argue that less-than-ideal experimental conditions, and factors such as dispersal conditioned on sex are likely to play a larger role that the type of conditional dispersal studied here.},
}
@article {pmid22817537,
year = {2012},
author = {Markov, AV},
title = {Can kin selection facilitate the evolution of the genetic program of senescence?.},
journal = {Biochemistry. Biokhimiia},
volume = {77},
number = {7},
pages = {733-741},
doi = {10.1134/S0006297912070061},
pmid = {22817537},
issn = {1608-3040},
mesh = {Aging/*genetics ; *Biological Evolution ; Competitive Behavior ; *Computer Simulation ; Genetics, Population ; Models, Genetic ; *Selection, Genetic ; },
abstract = {The theory of adaptive senescence, or phenoptosis ("altruistic suicide" of the organism), implies that mutations enhancing mortality growth with age ("senescence genes") can be favored by selection under some circumstances, although the nature of these circumstances and the frequency of their occurrence are not clear. Here I demonstrate by means of computer simulation that senescence genes can spread in the population's gene pool via the mechanism of kin selection if two conditions are met. First, the population must have high viscosity (low intermixing), which provides positive correlation between spatial proximity of individuals and their relatedness, an important precondition for kin selection. Second, prior to acquisition of the senescence genes, there must be a sufficiently fast decline in the reproductive potential with age, while viability should decrease slower or remain constant. These conditions are probably met in some territorial and social species with severe competition for social rank and mating partners.},
}
@article {pmid22787025,
year = {2012},
author = {Browning, LE and Patrick, SC and Rollins, LA and Griffith, SC and Russell, AF},
title = {Kin selection, not group augmentation, predicts helping in an obligate cooperatively breeding bird.},
journal = {Proceedings. Biological sciences},
volume = {279},
number = {1743},
pages = {3861-3869},
doi = {10.1098/rspb.2012.1080},
pmid = {22787025},
issn = {1471-2954},
mesh = {Animals ; *Cooperative Behavior ; New South Wales ; *Reproduction ; Seasons ; *Selection, Genetic ; Songbirds/*physiology ; },
abstract = {Kin selection theory has been the central model for understanding the evolution of cooperative breeding, where non-breeders help bear the cost of rearing young. Recently, the dominance of this idea has been questioned; particularly in obligate cooperative breeders where breeding without help is uncommon and seldom successful. In such systems, the direct benefits gained through augmenting current group size have been hypothesized to provide a tractable alternative (or addition) to kin selection. However, clear empirical tests of the opposing predictions are lacking. Here, we provide convincing evidence to suggest that kin selection and not group augmentation accounts for decisions of whether, where and how often to help in an obligate cooperative breeder, the chestnut-crowned babbler (Pomatostomus ruficeps). We found no evidence that group members base helping decisions on the size of breeding units available in their social group, despite both correlational and experimental data showing substantial variation in the degree to which helpers affect productivity in units of different size. By contrast, 98 per cent of group members with kin present helped, 100 per cent directed their care towards the most related brood in the social group, and those rearing half/full-sibs helped approximately three times harder than those rearing less/non-related broods. We conclude that kin selection plays a central role in the maintenance of cooperative breeding in this species, despite the apparent importance of living in large groups.},
}
@article {pmid22787022,
year = {2012},
author = {Rankin, DJ and Turner, LA and Heinemann, JA and Brown, SP},
title = {The coevolution of toxin and antitoxin genes drives the dynamics of bacterial addiction complexes and intragenomic conflict.},
journal = {Proceedings. Biological sciences},
volume = {279},
number = {1743},
pages = {3706-3715},
doi = {10.1098/rspb.2012.0942},
pmid = {22787022},
issn = {1471-2954},
support = {095831//Wellcome Trust/United Kingdom ; 082273//Wellcome Trust/United Kingdom ; },
mesh = {Antitoxins/*genetics/metabolism ; Bacteria/*genetics/metabolism ; Bacterial Toxins/antagonists & inhibitors/*genetics/metabolism ; Cell Death ; Chromosomes, Bacterial/*genetics/physiology ; *Evolution, Molecular ; Genetic Fitness ; Models, Biological ; Plasmids/*genetics/physiology ; },
abstract = {Bacterial genomes commonly contain 'addiction' gene complexes that code for both a toxin and a corresponding antitoxin. As long as both genes are expressed, cells carrying the complex can remain healthy. However, loss of the complex (including segregational loss in daughter cells) can entail death of the cell. We develop a theoretical model to explore a number of evolutionary puzzles posed by toxin-antitoxin (TA) population biology. We first extend earlier results demonstrating that TA complexes can spread on plasmids, as an adaptation to plasmid competition in spatially structured environments, and highlight the role of kin selection. We then considered the emergence of TA complexes on plasmids from previously unlinked toxin and antitoxin genes. We find that one of these traits must offer at least initially a direct advantage in some but not all environments encountered by the evolving plasmid population. Finally, our study predicts non-transitive 'rock-paper-scissors' dynamics to be a feature of intragenomic conflict mediated by TA complexes. Intragenomic conflict could be sufficient to select deleterious genes on chromosomes and helps to explain the previously perplexing observation that many TA genes are found on bacterial chromosomes.},
}
@article {pmid22777019,
year = {2012},
author = {Pizzari, T and Gardner, A},
title = {The sociobiology of sex: inclusive fitness consequences of inter-sexual interactions.},
journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences},
volume = {367},
number = {1600},
pages = {2314-2323},
doi = {10.1098/rstb.2011.0281},
pmid = {22777019},
issn = {1471-2970},
mesh = {Altruism ; Animals ; Competitive Behavior/*physiology ; *Conflict (Psychology) ; Cooperative Behavior ; Female ; Fertility ; *Genetic Fitness ; *Interpersonal Relations ; Male ; Selection, Genetic ; *Sex ; Sexual Behavior, Animal/physiology ; *Sociobiology ; },
abstract = {The diversity of social interactions between sexual partners has long captivated biologists, and its evolution has been interpreted largely in terms of 'direct fitness' pay-offs to partners and their descendants. Inter-sexual interactions also have 'indirect effects' by affecting the fitness of relatives, with important consequences for inclusive fitness. However, inclusive fitness arguments have received limited consideration in this context, and definitions of 'direct' and 'indirect' fitness effects in this field are often inconsistent with those of inclusive fitness theory. Here, we use a sociobiology approach based on inclusive fitness theory to distinguish between direct and indirect fitness effects. We first consider direct effects: we review how competition leads to sexual conflict, and discuss the conditions under which repression of competition fosters sexual mutualism. We then clarify indirect effects, and show that greenbeard effects, kin recognition and population viscosity can all lead to episodes of indirect selection on sexual interactions creating potential for sexual altruism and spite. We argue that the integration of direct and indirect fitness effects within a sociobiology approach enables us to consider a more diverse spectrum of evolutionary outcomes of sexual interactions, and may help resolving current debates over sexual selection and sexual conflict.},
}
@article {pmid22777018,
year = {2012},
author = {Rubenstein, DR},
title = {Family feuds: social competition and sexual conflict in complex societies.},
journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences},
volume = {367},
number = {1600},
pages = {2304-2313},
doi = {10.1098/rstb.2011.0283},
pmid = {22777018},
issn = {1471-2970},
mesh = {Altruism ; Animals ; Biological Evolution ; Choice Behavior ; Competitive Behavior/*physiology ; *Conflict (Psychology) ; Cooperative Behavior ; Female ; Male ; Pair Bond ; Reproduction ; Sex Characteristics ; Sexual Behavior, Animal/*physiology ; },
abstract = {Darwin was initially puzzled by the processes that led to ornamentation in males-what he termed sexual selection-and those that led to extreme cooperation and altruism in complex animal societies-what was later termed kin selection. Here, I explore the relationships between sexual and kin selection theory by examining how social competition for reproductive opportunities-particularly in females-and sexual conflict over mating partners are inherent and critical parts of complex altruistic societies. I argue that (i) patterns of reproductive sharing within complex societies can drive levels of social competition and reproductive conflict not only in males but also in females living in social groups, and ultimately the evolution of female traits such as ornaments and armaments; (ii) mating conflict over female choice of sexual partners can influence kin structure within groups and drive the evolution of complex societies; and (iii) patterns of reproductive sharing and conflict among females may also drive the evolution of complex societies by influencing kin structure within groups. Ultimately, complex societies exhibiting altruistic behaviour appear to have only arisen in taxa where social competition over reproductive opportunities and sexual conflict over mating partners were low. Once such societies evolved, there were important selective feedbacks on traits used to regulate and mediate intra-sexual competition over reproductive opportunities, particularly in females.},
}
@article {pmid22777013,
year = {2012},
author = {Rubenstein, DR},
title = {Sexual and social competition: broadening perspectives by defining female roles.},
journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences},
volume = {367},
number = {1600},
pages = {2248-2252},
doi = {10.1098/rstb.2011.0278},
pmid = {22777013},
issn = {1471-2970},
mesh = {Animals ; Biological Evolution ; Choice Behavior/*physiology ; Competitive Behavior/*physiology ; Conflict (Psychology) ; Female ; Genetic Fitness/physiology ; Interpersonal Relations ; Male ; Mating Preference, Animal/*physiology ; Sex Characteristics ; },
abstract = {Males figured more prominently than females in Darwin's view of sexual selection. He considered female choice of secondary importance to male-male competition as a mechanism to explain the evolution of male ornaments and armaments. Fisher later demonstrated the importance of female choice in driving male trait evolution, but his ideas were largely ignored for decades. As sexual selection came to embrace the notions of parent-offspring and sexual conflict, and experimental tests of female choice showed promise, females began to feature more prominently in the framework of sexual selection theory. Recent debate over this theory has centred around the role of females, not only over the question of choice, but also over female-female competition. Whereas some have called for expanding the sexual selection framework to encompass all forms of female-female competition, others have called for subsuming sexual selection within a broader framework of social selection, or replacing it altogether. Still others have argued for linking sexual selection more clearly to other evolutionary theories such as kin selection. Rather than simply debating terminology, we must take a broader view of the general processes that lead to trait evolution in both sexes by clearly defining the roles that females play in the process, and by focusing on intra- and inter-sexual interactions in males and females.},
}
@article {pmid22776671,
year = {2012},
author = {Bao, M and Wild, G},
title = {Reproductive skew can provide a net advantage in both conditional and unconditional social interactions.},
journal = {Theoretical population biology},
volume = {82},
number = {3},
pages = {200-208},
doi = {10.1016/j.tpb.2012.06.006},
pmid = {22776671},
issn = {1096-0325},
mesh = {Altruism ; Humans ; *Interpersonal Relations ; },
abstract = {We revisit a model for the evolution of costly social behaviour in the presence of reproductive skew. The model population is structured into groups, and reproductive skew is captured by assuming individuals adopt one of two social roles (dominant/subordinate). Unlike previous work, we adopt an ultimate perspective by tracking a mutant allele over the entire course of an invasion. Our main analysis applies the theory of branching processes, but a parallel analysis using the inclusive-fitness approach is also provided. Our first two results are modifications of known inequalities describing selective advantages for behaviours expressed conditional upon social status. We find that altruistic subordinate individuals are favoured more readily than previously thought; spiteful dominant individuals, however, are favoured less readily. Secondly, we identify the condition under which unconditional altruism (performed by both dominant and subordinate) will be adaptive. Our third main result shows that increasing the strength of selection can also change the range of parameters over which costly social behaviours are favoured. We find that stronger selection makes it relatively easier for subordinate altruism to emerge, but more difficult for dominant spite and unconditional altruism to occur. We discuss the possible implications of our results for human social evolution.},
}
@article {pmid22774787,
year = {2013},
author = {Archer, J},
title = {Can evolutionary principles explain patterns of family violence?.},
journal = {Psychological bulletin},
volume = {139},
number = {2},
pages = {403-440},
doi = {10.1037/a0029114},
pmid = {22774787},
issn = {1939-1455},
mesh = {Age Factors ; *Biological Evolution ; Domestic Violence/*psychology ; *Family Relations ; Female ; Humans ; Male ; Parents/psychology ; Paternity ; Sexual Partners/psychology ; Siblings/psychology ; },
abstract = {The article's aim is to evaluate the application of the evolutionary principles of kin selection, reproductive value, and resource holding power to the understanding of family violence. The principles are described in relation to specific predictions and the mechanisms underlying these. Predictions are evaluated for physical violence perpetrated by (a) parents to unrelated children, (b) parents to genetic offspring, and (c) offspring to parents and between (d) siblings and (e) sexual partners. Precise figures for risks have been calculated where possible. The major conclusions are that most of the evidence is consistent with evolutionary predictions derived from kin selection and reproductive value: There were (a) higher rates of violence to stepchildren, (b) a decline in violence with the age of offspring, and (c) an increase in violence with parental age, while (d) violence between siblings was generally at a low level and concerned resource disputes. The issue of distinguishing evolutionary from alternative explanations is addressed throughout and is problematic for predictions derived from reproductive value. The main evolutionary explanation for male partner violence, mate guarding as a result of paternity uncertainty, cannot explain Western studies where sex differences in control and violence between partners were absent, although other aspects of male partner violence are consistent with it, and it may explain sex differences in traditional cultures. Recurrent problems in evaluating the evidence were to control for possible confounds and thus to distinguish evolutionary from alternative explanations. Suggestions are outlined to address this and other issues arising from the review.},
}
@article {pmid22774226,
year = {2012},
author = {Yeh, AY and Gardner, A},
title = {A general ploidy model for the evolution of helping in viscous populations.},
journal = {Journal of theoretical biology},
volume = {304},
number = {},
pages = {297-303},
pmid = {22774226},
issn = {1095-8541},
mesh = {Animals ; *Biological Evolution ; Competitive Behavior ; Female ; *Helping Behavior ; Male ; *Models, Genetic ; *Ploidies ; Population Dynamics ; Reproduction ; Selection, Genetic/genetics ; Sexual Behavior, Animal ; },
abstract = {There is growing interest in understanding how kin selection drives the evolution of social behaviours in viscous populations. A key result, that has inspired much work on this topic, is the exact cancellation of the genetic relatedness and kin competition effects of dispersal in the simplest models of population viscosity, such that a reduction in the rate of dispersal neither promotes nor inhibits the evolution of helping behaviour. This theoretical result has been demonstrated for populations characterised by haploid, diploid and haplodiploid modes of inheritance. Here we develop a model of general ploidy that recovers these three scenarios as special cases and allows examination of scenarios that have not been considered previously. Specifically, we: clarify the importance of the implicit assumption of monandry in previous models; show that the cancellation result obtains in some models of ploidy but not in others; and reveal that the cancellation result obtains for different reasons in different models of ploidy. The cancellation result therefore hinges upon a population's genetic system as well as its demography.},
}
@article {pmid22759286,
year = {2012},
author = {Hall, DW and Goodisman, MA},
title = {The effects of kin selection on rates of molecular evolution in social insects.},
journal = {Evolution; international journal of organic evolution},
volume = {66},
number = {7},
pages = {2080-2093},
doi = {10.1111/j.1558-5646.2012.01602.x},
pmid = {22759286},
issn = {1558-5646},
mesh = {Alleles ; Animals ; Ants/genetics ; Bees/genetics ; *Evolution, Molecular ; Female ; Insecta/*genetics ; Male ; Models, Genetic ; *Selection, Genetic ; Social Behavior ; },
abstract = {The evolution of sociality represented a major transition point in biological history. The most advanced societies, such as those displayed by social insects, consist of reproductive and nonreproductive castes. The caste system fundamentally affects the way natural selection operates. Specifically, selection acts directly on reproductive castes, such as queens, but only indirectly through the process of kin selection on nonreproductive castes, such as workers. In this study, we present theoretical analyses to determine the rate of substitution at loci expressed exclusively in the queen or worker castes. We show that the rate of substitution is the same for queen- and worker-selected loci when the queen is singly mated. In contrast, when a queen is multiply mated, queen-selected loci show higher rates of substitution for adaptive alleles and lower rates of substitution for deleterious alleles than worker-selected loci. We compare our theoretical expectations to previously obtained genomic data from the honeybee, Apis mellifera, where queens mate multiply and the fire ant, Solenopsis invicta, where queens mate singly and find that rates of evolution of queen- and worker-selected loci are consistent with our predictions. Overall, our research tests theoretical expectations using empirically obtained genomic data to better understand the evolution of advanced societies.},
}
@article {pmid22759285,
year = {2012},
author = {Rodrigues, AM and Gardner, A},
title = {Evolution of helping and harming in heterogeneous populations.},
journal = {Evolution; international journal of organic evolution},
volume = {66},
number = {7},
pages = {2065-2079},
doi = {10.1111/j.1558-5646.2012.01594.x},
pmid = {22759285},
issn = {1558-5646},
mesh = {Animals ; *Biological Evolution ; *Environment ; Genetic Variation ; *Helping Behavior ; Models, Genetic ; *Selection, Genetic ; },
abstract = {There has been much interest in understanding how demographic factors can mediate social evolution in viscous populations. Here, we examine the impact of heterogeneity in patch quality--that is, the availability of reproductive resources for each breeder--upon the evolution of helping and harming behaviors. We find that, owing to a cancellation of relatedness and kin competition effects, the evolution of obligate and facultative helping and harming is not influenced by the degree of viscosity in populations characterized by either spatial or temporal heterogeneity in patch quality. However, facultative helping and harming may be favored when there is both spatial and temporal heterogeneity in patch quality, with helping and harming being favored in both high-quality and low-quality patches. We highlight the prospect for using kin selection theory to explain within-population variation in social behavior, and point to the need for further theoretical and empirical investigation of this topic.},
}
@article {pmid22694128,
year = {2012},
author = {Gardner, A},
title = {Evolution of maternal care in diploid and haplodiploid populations.},
journal = {Journal of evolutionary biology},
volume = {25},
number = {8},
pages = {1479-1486},
doi = {10.1111/j.1420-9101.2012.02551.x},
pmid = {22694128},
issn = {1420-9101},
mesh = {Animals ; *Biological Evolution ; *Diploidy ; Female ; *Haploidy ; *Maternal Behavior ; *Models, Biological ; Social Behavior ; },
abstract = {Maternal care has been suggested to evolve more readily in haplodiploid populations. Because maternal care appears to have been a prerequisite for the evolution of eusociality, this effect potentially explains the apparent preponderance of haplodiploidy among eusocial taxa. Here, I use a kin selection approach to model the evolution of maternal care in diploid and haplodiploid populations. In contrast to previous suggestions, I find that haplodiploidy may inhibit as well as promote the evolution of maternal care. Moreover, I find that the haplodiploidy effect vanishes in outbred populations if gene effects average rather than add together. I confirm these analytical results using numerical simulation of an explicit population genetics model. This analysis casts doubt upon the idea that haplodiploidy has promoted the evolution of maternal care and, consequently, the evolution of eusociality.},
}
@article {pmid22648154,
year = {2012},
author = {Rumbaugh, KP and Trivedi, U and Watters, C and Burton-Chellew, MN and Diggle, SP and West, SA},
title = {Kin selection, quorum sensing and virulence in pathogenic bacteria.},
journal = {Proceedings. Biological sciences},
volume = {279},
number = {1742},
pages = {3584-3588},
doi = {10.1098/rspb.2012.0843},
pmid = {22648154},
issn = {1471-2954},
mesh = {Animals ; Bacterial Proteins/genetics ; Female ; Liver/microbiology ; Mice ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/genetics/*pathogenicity/*physiology ; *Quorum Sensing ; *Selection, Genetic ; Skin/microbiology ; Trans-Activators/genetics ; Virulence ; Wounds and Injuries/microbiology/pathology ; },
abstract = {Bacterial growth and virulence often depends upon the cooperative release of extracellular factors excreted in response to quorum sensing (QS). We carried out an in vivo selection experiment in mice to examine how QS evolves in response to variation in relatedness (strain diversity), and the consequences for virulence. We started our experiment with two bacterial strains: a wild-type that both produces and responds to QS signal molecules, and a lasR (signal-blind) mutant that does not release extracellular factors in response to signal. We found that: (i) QS leads to greater growth within hosts; (ii) high relatedness favours the QS wild-type; and (iii) low relatedness favours the lasR mutant. Relatedness matters in our experiment because, at relatively low relatedness, the lasR mutant is able to exploit the extracellular factors produced by the cells that respond to QS, and hence increase in frequency. Furthermore, our results suggest that because a higher relatedness favours cooperative QS, and hence leads to higher growth, this will also lead to a higher virulence, giving a relationship between relatedness and virulence that is in the opposite direction to that usually predicted by virulence theory.},
}
@article {pmid22647036,
year = {2012},
author = {Arora, N and Van Noordwijk, MA and Ackermann, C and Willems, EP and Nater, A and Greminger, M and Nietlisbach, P and Dunkel, LP and Utami Atmoko, SS and Pamungkas, J and Perwitasari-Farajallah, D and Van Schaik, CP and Krützen, M},
title = {Parentage-based pedigree reconstruction reveals female matrilineal clusters and male-biased dispersal in nongregarious Asian great apes, the Bornean orang-utans (Pongo pygmaeus).},
journal = {Molecular ecology},
volume = {21},
number = {13},
pages = {3352-3362},
doi = {10.1111/j.1365-294X.2012.05608.x},
pmid = {22647036},
issn = {1365-294X},
mesh = {Animals ; DNA, Mitochondrial/genetics ; Female ; *Genetic Variation ; *Genetics, Population ; Haplotypes ; Male ; Molecular Sequence Data ; Pedigree ; Pongo pygmaeus/*genetics ; Sequence Analysis, DNA ; },
abstract = {Philopatry and sex-biased dispersal have a strong influence on population genetic structure, so the study of species dispersal patterns and evolutionary mechanisms shaping them are of great interest. Particularly nongregarious mammalian species present an underexplored field of study: despite their lower levels of sociality compared to group-living species, interactions among individuals do occur, providing opportunities for cryptic kin selection. Among the least gregarious primates are orang-utans (genus: Pongo), in which preferential associations among females have nevertheless been observed, but for which the presence of kin structures was so far unresolved because of the equivocal results of previous genetic studies. To clarify relatedness and dispersal patterns in orang-utans, we examined the largest longitudinal set of individuals with combined genetic, spatial and behavioural data. We found that males had significantly higher mitochondrial DNA (mtDNA) variation and more unique haplotypes, thus underscoring their different maternal ancestries compared to females. Moreover, pedigree reconstruction based on 24 highly polymorphic microsatellite markers and mtDNA haplotypes demonstrated the presence of three matrilineal clusters of generally highly related females with substantially overlapping ranges. In orang-utans and possibly other nongregarious species, comparing average biparental relatedness (r) of males and females to infer sex-biased dispersal is extremely problematic. This is because the opportunistic sampling regime frequently employed in nongregarious species, combined with overlapping space use of distinct matrilineal clusters, leads to a strong downward bias when mtDNA lineage membership is ignored. Thus, in nongregarious species, correct inferences of dispersal can only be achieved by combining several genetic approaches with detailed spatial information.},
}
@article {pmid22593110,
year = {2012},
author = {Dickins, TE and Rahman, Q},
title = {The extended evolutionary synthesis and the role of soft inheritance in evolution.},
journal = {Proceedings. Biological sciences},
volume = {279},
number = {1740},
pages = {2913-2921},
doi = {10.1098/rspb.2012.0273},
pmid = {22593110},
issn = {1471-2954},
mesh = {Adaptation, Biological ; Animals ; *Biological Evolution ; *Epigenesis, Genetic ; *Heredity ; Humans ; Mice ; },
abstract = {In recent years, a number of researchers have advocated extending the modern synthesis in evolutionary biology. One of the core arguments made in favour of an extension comes from work on soft inheritance systems, including transgenerational epigenetic effects, cultural transmission and niche construction. In this study, we outline this claim and then take issue with it. We argue that the focus on soft inheritance has led to a conflation of proximate and ultimate causation, which has in turn obscured key questions about biological organization and calibration across the life span to maximize average lifetime inclusive fitness. We illustrate this by presenting hypotheses that we believe incorporate the core phenomena of soft inheritance and will aid in understanding them.},
}
@article {pmid22579553,
year = {2012},
author = {Ohtsuki, H},
title = {Does synergy rescue the evolution of cooperation? An analysis for homogeneous populations with non-overlapping generations.},
journal = {Journal of theoretical biology},
volume = {307},
number = {},
pages = {20-28},
doi = {10.1016/j.jtbi.2012.04.030},
pmid = {22579553},
issn = {1095-8541},
mesh = {*Biological Evolution ; *Cooperative Behavior ; Genetic Fitness ; *Models, Biological ; Phylogeny ; Population Dynamics ; Selection, Genetic ; },
abstract = {Recent developments of social evolution theory have revealed conditions under which cooperation is favored by natural selection. Effects of population structure on the evolution of cooperation have been one of the central questions in this issue, and inclusive fitness analyses have unveiled two different selective forces that favor cooperation; the direct fitness effect to the helper and the indirect fitness benefit to the helper via its kin. Although these theoretical frameworks have made a significant contribution to our understanding of cooperative traits, there is still one factor to be taken into account, synergy. Synergy means a nonlinear effect that arises when two individuals help each other. In other words, it represents deviation from additivity, to which inclusive fitness theory has paid relatively little attention. Here I provide a theoretical result on the possibility that synergy favors the evolution of cooperation. For homogeneously structured populations with non-overlapping generations, I show that incorporating synergistic effects does not rescue the evolution of cooperation. Potential factors that could enable synergy to rescue the evolution of cooperation are also discussed.},
}
@article {pmid22568752,
year = {2012},
author = {Jaatinen, K and Noreikiene, K and Merilä, J and Ost, M},
title = {Kin association during brood care in a facultatively social bird: active discrimination or by-product of partner choice and demography?.},
journal = {Molecular ecology},
volume = {21},
number = {13},
pages = {3341-3351},
doi = {10.1111/j.1365-294X.2012.05603.x},
pmid = {22568752},
issn = {1365-294X},
mesh = {Animals ; Anseriformes/*genetics/physiology ; Female ; *Genetics, Population ; Genotype ; Microsatellite Repeats ; *Nesting Behavior ; Population Density ; Sequence Analysis, DNA ; *Social Behavior ; },
abstract = {Intra-group relatedness does not necessarily imply kin selection, a leading explanation for social evolution. An overlooked mechanism for generating population genetic structure is variation in longevity and fecundity, referred to as individual quality, affecting kin structure and the potential for cooperation. Individual quality also affects choosiness in partner choice, a key process explaining cooperation through direct fitness benefits. Reproductive skew theory predicts that relatedness decreases with increasing group size, but this relationship could also arise because of quality-dependent demography and partner choice, without active kin association. We addressed whether brood-rearing eider (Somateria mollissima) females preferentially associated with kin using a 6-year data set with individuals genotyped at 19 microsatellite loci and tested whether relatedness decreased with increasing female group size. We also determined the relationship between local relatedness and indices of female age and body condition. We further examined whether the level of female intracoalition relatedness differed from background relatedness in any year. As predicted, median female intra-group relatedness decreased with increasing female group size. However, the proportion of related individuals increased with advancing female age, and older females prefer smaller brood-rearing coalitions, potentially producing a negative relationship between group size and relatedness. There were considerable annual fluctuations in the level of relatedness between coalition-forming females, and in 1year this level exceeded that expected by random association. Thus, both passive and active mechanisms govern kin associations in brood-rearing eiders. Eiders apparently can discriminate between kin, but the benefits of doing so may vary over time.},
}
@article {pmid22544168,
year = {2012},
author = {Nesse, RM and Ganten, D and Gregory, TR and Omenn, GS},
title = {Evolutionary molecular medicine.},
journal = {Journal of molecular medicine (Berlin, Germany)},
volume = {90},
number = {5},
pages = {509-522},
doi = {10.1007/s00109-012-0889-9},
pmid = {22544168},
issn = {1432-1440},
support = {U54ES017885/ES/NIEHS NIH HHS/United States ; U54DA021519/DA/NIDA NIH HHS/United States ; P30 ES017885/ES/NIEHS NIH HHS/United States ; U54 DA021519/DA/NIDA NIH HHS/United States ; UL1 RR024986/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Disease/genetics ; *Evolution, Molecular ; Genetic Pleiotropy ; Humans ; *Medicine ; Polymorphism, Genetic ; Selection, Genetic ; },
abstract = {Evolution has long provided a foundation for population genetics, but some major advances in evolutionary biology from the twentieth century that provide foundations for evolutionary medicine are only now being applied in molecular medicine. They include the need for both proximate and evolutionary explanations, kin selection, evolutionary models for cooperation, competition between alleles, co-evolution, and new strategies for tracing phylogenies and identifying signals of selection. Recent advances in genomics are transforming evolutionary biology in ways that create even more opportunities for progress at its interfaces with genetics, medicine, and public health. This article reviews 15 evolutionary principles and their applications in molecular medicine in hopes that readers will use them and related principles to speed the development of evolutionary molecular medicine.},
}
@article {pmid22498803,
year = {2012},
author = {Seki, M},
title = {Intra-individual conflicts between autosomal and X-linked altruistic genes: evolutionary perspectives of sex-specific grandmothering.},
journal = {Journal of theoretical biology},
volume = {304},
number = {},
pages = {273-285},
doi = {10.1016/j.jtbi.2012.03.032},
pmid = {22498803},
issn = {1095-8541},
mesh = {*Altruism ; *Biological Evolution ; Female ; Game Theory ; *Genes, X-Linked ; Humans ; *Intergenerational Relations ; Male ; *Models, Genetic ; Residence Characteristics ; Selection, Genetic/genetics ; Sex Factors ; },
abstract = {Alloparental care by females toward their grandoffspring can evolve by kin selection. Previous theoretical studies predicted that selection favors autosomal and X-chromosomal genes, causing altruism toward maternal grandoffspring and paternal granddaughters, respectively, and two corresponding types of biased grandparental investment are suggested by empirical studies on human populations. Using discrete-time two-locus-two-allele models, I examined a possible conflict between the autosomal and the X-chromosomal altruistic genes over the carrier female's time and resources. This conflict is expected to occur when each grandmother has access to only maternal or paternal grandchildren as a result of her residence situation. The conditions under which each or both kinds of altruistic genes evolve (against non-altruistic genes) mainly represent the conflicting relationship between the autosomal and X-chromosomal altruistic genes. In addition, depending on the settings, the models exhibit bistable or periodic behaviors, and one type of gene can be considered parasitic in the latter behavior. On the whole, the results suggest that the X-chromosomal altruistic genes rather than the autosomal ones exhibit more difficulty increasing or fixing with this kind of conflict.},
}
@article {pmid22496080,
year = {2012},
author = {Briga, M and Pen, I and Wright, J},
title = {Care for kin: within-group relatedness and allomaternal care are positively correlated and conserved throughout the mammalian phylogeny.},
journal = {Biology letters},
volume = {8},
number = {4},
pages = {533-536},
doi = {10.1098/rsbl.2012.0159},
pmid = {22496080},
issn = {1744-957X},
mesh = {Animals ; Bayes Theorem ; *Behavior, Animal ; Cooperative Behavior ; Female ; Mammals/classification/genetics/*psychology ; Maternal Behavior/*psychology ; Microsatellite Repeats ; *Phylogeny ; Population Density ; Reproduction ; Social Behavior ; Social Environment ; Species Specificity ; },
abstract = {With an increasing amount of data becoming available, comparative analyses have called attention to the associations between cooperative breeding, monogamy and relatedness. We focus here upon the association between allomaternal care and relatedness among females within a social unit. Previous studies found a positive association, but such results date back to before molecular tools were in common use, they considered only a few mammalian orders, neglected phylogenetic clustering and/or did not correct for group sizes. Here, we use molecular data on relatedness from 44 species of mammals to investigate the phylogenetic clustering of, and the association between, allomaternal care and relatedness among females within a social unit. We find (i) a strong phylogenetic signal for allomaternal care and a moderate one for relatedness and group size, and (ii) a positive association between relatedness and allomaternal care, even when correcting for the smaller than average group sizes in species with allomaternal care. We also find that, in species without allomaternal care, adult females often live with unrelated females even when groups are small. We discuss these results in the light of recent evidence for the role of kin selection and the monogamy hypothesis in cooperative breeding.},
}
@article {pmid22487312,
year = {2012},
author = {Frank, SA},
title = {Natural selection. IV. The Price equation.},
journal = {Journal of evolutionary biology},
volume = {25},
number = {6},
pages = {1002-1019},
doi = {10.1111/j.1420-9101.2012.02498.x},
pmid = {22487312},
issn = {1420-9101},
support = {U01 GM076499/GM/NIGMS NIH HHS/United States ; U01 GM076499-05/GM/NIGMS NIH HHS/United States ; U01 GM 76499/GM/NIGMS NIH HHS/United States ; },
mesh = {Animals ; *Biological Evolution ; Ecosystem ; Gene Frequency ; Genetics, Population ; Inheritance Patterns ; *Models, Statistical ; Phenotype ; Population Dynamics ; *Selection, Genetic ; },
abstract = {The Price equation partitions total evolutionary change into two components. The first component provides an abstract expression of natural selection. The second component subsumes all other evolutionary processes, including changes during transmission. The natural selection component is often used in applications. Those applications attract widespread interest for their simplicity of expression and ease of interpretation. Those same applications attract widespread criticism by dropping the second component of evolutionary change and by leaving unspecified the detailed assumptions needed for a complete study of dynamics. Controversies over approximation and dynamics have nothing to do with the Price equation itself, which is simply a mathematical equivalence relation for total evolutionary change expressed in an alternative form. Disagreements about approach have to do with the tension between the relative valuation of abstract versus concrete analyses. The Price equation's greatest value has been on the abstract side, particularly the invariance relations that illuminate the understanding of natural selection. Those abstract insights lay the foundation for applications in terms of kin selection, information theory interpretations of natural selection and partitions of causes by path analysis. I discuss recent critiques of the Price equation by Nowak and van Veelen.},
}
@article {pmid22483741,
year = {2012},
author = {Drewell, RA and Lo, N and Oxley, PR and Oldroyd, BP},
title = {Kin conflict in insect societies: a new epigenetic perspective.},
journal = {Trends in ecology & evolution},
volume = {27},
number = {7},
pages = {367-373},
doi = {10.1016/j.tree.2012.02.005},
pmid = {22483741},
issn = {1872-8383},
mesh = {Animals ; *DNA Methylation ; Female ; *Genomic Imprinting ; *Insecta ; Male ; Mammals/genetics/growth & development ; *Social Behavior ; },
abstract = {The social hymenopterans (ants, wasps and bees) have all the enzymatic and genetic mechanisms necessary for the functional modification of DNA by methylation. Methylation appears to play a central role in shaping the developmental processes that give rise to the different castes. However, could DNA methylation have other roles in social insects? Theoretical arguments predict that male and female hymenopterans can be in conflict over the reproductive potential